Как проверить диодную лампочку мультиметром: Проверка лампочки мультиметром: тестирование разных ламп

Как проверить светодиод тестером — прозвонить мультиметром?

Светодиод – полупроводниковый прибор, по своей структуре напоминающий обычный диод. Поэтому проверить его можно как обычный диод — включением в прямом направлении, т.е. между анодом и катодом приложить положительное напряжение. Проверка не составит труда, если есть на руках обычный тестер. В отличие от обычных кремниевых диодов, прямое напряжение на которых составляет 0,6…0,7 В, светодиод имеет гораздо большее значение этого параметра. В зависимости от цвета и материала, красные имеют напряжение – 1,5…2 В, зеленые – 1,9…4 В, белые – около 3…3,5 В. Эта информация указана в документации производителя.

Еще одной особенностью светоизлучающего диода от обычного – низкое обратное напряжение, которое превышает прямое всего на несколько вольт. Это повышает риск выхода прибора из строя при неправильном включении или вследствие электростатического разряда. Как убедиться в исправности светодиода, прежде чем смонтировать его на плату?

Практически любой цифровой тестер (или мультиметр, кому как больше нравится) позволяет быстро проверить светодиод на работоспособность.

В простейшем случае, чтобы прозвонить светодиод, нужно включить мультиметр в режим проверки диодов, как показано на рисунке ниже.

Далее определим полярность включения. У выводных светодиодов катод обычно короче анода. Если выводы одинаковой длины (кто-то «заботливо» обкусил), то смотрим на просвет. На рисунке видно, что внутри самого корпуса располагаются два электрода, обычно тот который большего размера – катод, но это не всегда так, поэтому не стоит брать это за правило.

Остается только подключить тестер к выводам светодиода. Красный щуп к аноду, черный – к катоду (если, конечно, у вас стандартные цвета щупов). Исправность определяется по свечению.

Этим же способом можно проверить и мощный светодиод. Такие обычно смонтированы на плату с металлической подложкой (MCPCB). Полярность обычно подписана рядом с контактными площадками. Если нет, тогда наугад. Вероятность повредить светодиод тестером очень мала – не та мощность.

Еще проще и удобнее прозвонить выводные светодиоды, если в мультиметре есть функция проверки транзисторов. В этом случае нужно всего лишь вставить в соответствующий разъем выводы. Для секции NPN: анод в отверстие С (коллектор), катод в E (эмиттер). Для секции PNP – с точностью до наоборот. Наглядно проверка показана на рисунке ниже.

Когда дело касается мощных осветительных светодиодов, работающих на токах порядка сотен и тысяч мА, то встречается такой дефект: при «прозвонке» светодиод подсвечивается и признается годным, а когда включается на рабочий ток, то светит словно «в полнакала». Это связано с дефектом кристалла и если замена бракованных светодиодов в готовом изделии (например, прожекторе) затруднена, то необходимо проверить их заранее.

Более тщательная проверка, помимо мультиметра, потребует еще и источника тока. Идеальный вариант – наличие лабораторного источника, но подойдет и адаптер для зарядки мобильных телефонов или других устройств. Главное, чтобы он имел стабилизацию по току.

Последовательность такова:

1. мультиметр переключаем на предел «10 А» (не забываем переставить щуп в соответствующее гнездо) и включаем в цепь последовательно между светодиодом и источником питания;
2. включаем питание, измеряем силу тока, выключаем питание;
3. мультиметр включаем параллельно светодиоду, установив предел измерения «20 В» (опять же не забывая переставить щуп, а то устроим КЗ), источник соединяем напрямую со светодиодом, соблюдая полярность;
4. включаем питание, измеряем падение напряжения на светодиоде, выключаем питание;
5. проверяем исправность по соответствию тока и напряжения по кривой вольтамперной характеристики, приведенной производителем в data sheet.

90000 How to Test a Diode using Digital & Analog Multimeter 90001 90002 90003 Test a Diode by Analog & Digital Multimeter 90004 90005 90006 90003 Troubleshooting Electronic Devices & Components 90004 90009 90010 Troubleshooting in electronic and electrical engineering is an important part and one must know the basic skills and knowledge about the components to design and troubleshoot a circuit. It is advisable to test component before assembling and placing in a circuit. 90011 90010 Sometimes, we get unexpected results and we must perform some tests to find whether the component and device is working properly or we should replaced with a new one.For this purpose, we have started some Digital and Analog multimeters tutorials where we will discus how to test different electrical and electronics components. Today, we will have to discuss how to test a diode using DMM and AMM by 4 methods. 90011 90006 90003 How to Test a Diode 90016 90004 90009 90010 Diode is a simple PN Junction and two terminal device which allow to flow current though it in one direction (Forward Bias). It is the most used component in different electronic designs and systems like rectifiers, LED lights related circuits, voltage multiplying circuits, solar panels, logic gates etc.90011 90021 90021 Diode Terminal Identification (Anode + Cathode) 90010 When the cathode terminal of diode is connected to the neutral and anode to positive, It is called in forward bias position and it acts like a short switch where current starts to flow through it. Cathode to positive and anode to neutral is called reverse bias and diode is acts as open switch which is know as reverse bias (This case is reverse in case of zener diode). 90011 90010 Before testing a diode, We must know the diode terminals like Anode (+) and Cathode (-).In most cases, there is a white band color coating on normal PN junctions diodes which indicates as cathode terminal and the rest is anode. In other cases, there are different colors are used and the color coated sides are cathode as shown in fig below. Below is a tutorial that shows how to test a normal PN Diode, LED, and Zener Diode by different methods .. 90011 90010 Diode can be check and tested by 4 methods using digital or analog multimeters. 90011 90006 90003 How to Test a Diode using Digital Multimeter 90004 90009 90010 90034 90003 Testing Diode using DMM (Diode Test Mode + Resistance Mode) 90004 90037 90011 90039 90039 Testing Diode using DMM (Diode Test Mode + Resistance Mode) 90010 The best practice to test a diode in «Diode test» mode by measuring the voltage drop across the diode in case of forward biased.Keep in mind that diode in forward-biased acts as closed switch which let to flow current in it like conductors. In reverse-biased diode, it acts like an open switch and does not permit current to flow in it as it acts like a resistor. 90011 90010 Forward Biased: When the Positive (Red) test lead is connected to the anode (+) and negative (Black) test lead is connected to the cathode (-) of diode. In Forward-biased, the diode acts like close switch and will pass the current through it like conductors.90011 90010 Reverse Biased: If we do the reverse as mention above i.e. RED Test lead to cathode (-) and BLACK test lead to the Anode (+) of the diode. In revere-biased, the diode acts like open switch and will not let pass the current through it like resistor. 90011 90010 Steps: 90011 90049 90050 Remove the diode from the circuit i.e. disconnect the power supply across the diode which has to be tested. Discharge all the capacitor (by shorting the capacitor leads) in the circuit (If any). 90051 90050 Set the meter on «Diode Test» Mode by turning the rotary switch of multimeter.90051 90050 Connect the diode leads to the multimeter test leads and note the reading. 90051 90050 Now, Connect the diode lead to the multimeter test leads in reverse direction (i.e. Reverse the test leads) and note the measurement. 90051 90058 90059 90050 If the multimeter shows 0.5V — 0.8V for common silicon diodes and 0.2V- 0.3V in case of germanium diodes in the first attempt, its mean the diode is in good condition (forward-biased). 90051 90050 If multimeter display «OL» in reverse biased, It is good as well.90051 90050 If multimeter does not show measurements I.e. if multimeter display «OL» reading in both direction (Forward-biased and reverse-biased), its mean diode is dead and acting as an open switch which does not allow current to flow in it. In case of shorted diode, there will be zero voltage drop across the diode as current will flow through it and it acts like a short path for current. The diode needs to be changed then. 90051 90050 If the multimeter displays approximately 0.4V in both directions, its mean the diode is short and need to be replaced with new one.90051 90068 90010 Related Tutorial: How to find The value of Burnt Resistor (By three handy Methods) 90011 90006 90003 How to Test a Diode using Analog Multimeter 90004 90009 90010 90034 90003 Testing Diode by Multimeter (DMM & AMM in Resistance Mode) 90004 90037 90011 90010 If «diode test is not available in case of digital multimeter or you have to test the diode with analog multimeter, Resistance mode (Ω) can be used to test the diode as alternative. 90011 90010 Click image to enlarge 90011 90085 90085 Testing Diode by Multimeter (DMM & AMM in Resistance Mode) 90010 Steps: 90011 90049 90050 Remove the diode from the circuit and make sure that power supply is disconnected from the circuit and there is no voltage across the diode which has to be tested.Also, discharge all the capacitors by shorting their leads in the circuits if any. 90051 90050 Set the meter on «Resistance mode (Ω)» Mode by turning the rotary switch of multimeter. For better result, set the Ω range on 1kΩ for forward bias and 100kΩ for reverse bias as shown in fig below. 90051 90050 Connect the RED test lead to the anode of the diode and BLACK test lead to the cathode of diode (Forward Bias) as shown in fig. Note the measurement and reading. 90051 90050 Now reverse the test leads i.e. RED test lead to cathode and BLACK to anode (Reverse Bias) and note the reading and measurement displayed by multimeter. 90051 90058 90059 90050 If multimeter shows 1k Ω to 10 MΩ (not OL or infinite ∞), its mean the diode is in good condition (forward-biased). Mostly, the best value is below 1kΩ i.e. for good diode, the forward bias resistance should be low. 90051 90050 If multimeter shows «OL» in reverse biased. The diode is good as well. 90051 90050 If the multimeter displays same reading and measurement in both directions (i.e. forward biased and reverse bias), its mean diode is bad and need to be replaced accordingly. 90051 90050 If multimeter shows the same results i.e. low resistance or high resistance (OL) in both direction (forward and reverse bias), the diode is short and open respectively. In other words, if the multimeter shows 0Ω resistance in both reverse and forward bias, the diode is short, if ohmmeter shows ∞, OL or very high resistance in both forward and reverse bias, the diode is open and need to be replaced with new one.90051 90050 To make sure the result is accurate, the best practice is that test and compare the result of good diodes in Resistance Mode. 90051 90068 90010 Related Tutorial: How to test a battery with Test meter? 90011 90006 90003 How to test LED (Light Emitting Diode) 90004 90009 90010 Before testing a diode, we must identify the diode terminal i.e. anode and cathode. For LED, the longer terminal of diode is anode (+) and the shorter terminal is cathode (-). In other cases, the flat terminal of diode is cathode and the other side is anode as shown in below fig.90011 90010 Related Post: How to Calculate the Battery Charging Time & Battery Charging Current — Example 90011 90121 90121 LED Terminals Identification (Anode & Cathode) 90010 To test an LED with digital or analog multimeter, follow the instructions given below. 90011 90059 90050 Disconnect the LED from the circuit and power supply if it is already connected in a circuit. 90051 90050 Find the LED terminal i.e. anode and cathode (as shown in above fig) 90051 90050 In case of digital multimeter, set the meter on «Diode Test» Mode (in case of analog multimeter, set the multimeter on Resistance or continuity mode) by turning the rotary switch of multimeter .90051 90050 Connect the LED in forward biased with multimeter test leads i.e. cathode to black (-ve) and anode to Red (+ ve) test leads. 90051 90050 If the LED glows, it does not need to say it is in good condition and working properly, otherwise LED is defective and it should be changed. 90051 90050 In reverse biased (LED anode to Black (-ve) and cathode to Red (+ ve) test leads), it will not work and multimeter wont show any reading as LED will not flow current through it i.e. it acts like an open switch same as diode.90051 90068 90010 Related Post: How to Test & Fix the Printed Circuit Board (PCB) Defects? 90011 90006 90003 How to test Zener Diode 90004 90009 90010 Zener diode is something else as compared to normal diodes as simple PN junctions diodes operated in forward biased and not in reverse bias. The case is reverse in case of zener diode as it only operates in reverse based when the applied reverse voltage is greater than the zener breakdown voltage. This way, we need additional simple circuit to check whether the zener diode is good or bad.90011 90147 90147 Testing a Zener Diode by DMM & AMM 90010 To check a zener diode with digital or analog multimeter, follow the instructions below. 90011 90059 90050 Disconnect the zener diode from the circuit and power supply if it is already connected in a circuit. 90051 90050 Find the zener diode terminals i.e. anode and cathode as it is same as normal LED and PN junction diodes (as shown in above fig) 90051 90050 Connect the zener diode across a variable or known (such as 12V DC) supply voltage source in series of 100Ω resistance and then connect the zener diode reverse bias (cathode to Red (+ ve) and anode to Black (-ve) test leads of multimeter as shown in fig.90051 90050 In both of digital or analog multimeter, set the meter on «DC Voltage» test mode by turning the rotary switch of multimeter. 90051 90050 Increase the supply voltage gradually to the zener diode and note the meter reading displayed on screen. The meter reading should increase until the breakdown voltage of zener diode (in case of 12VDC supply voltage, the breakdown voltage is 6V) when you increase the supply voltage step by step from low to high. After this, meter should not show additional value i.e. it must shows a constant value (Such as 6V in case of 12VDC supply voltage). When meter stop at specific value and not showing another value when you still increasing the supply voltage, you should not continue to increase the supply voltage otherwise, diode may destroy. 90051 90050 If it is the case, the zener diode is in good condition otherwise, the zener diode is faulty and need to be changed. 90051 90068 90010 Related Posts: 90011.90000 How to Test a Transistor & Diode »Electronics Notes 90001 90002 It is very quick and easy to learn how to test a transistor and a diode with a analogue multimeter — normally this is good enough for most applications. 90003 90004 90005 90006 Multimeter Tutorial Includes: 90007 90008 Test meter basics Analogue multimeter How does an analogue multimeter work DMM digital multimeter How a DMM works DMM accuracy & resolution How to buy best digital multimeter How to use a multimeter Voltage measurement Current measurements Resistance measurements Diode & transistor test Fault finding transistor circuits 90009 90004 90005 While many digital multimeters these days have a specific capability for testing diodes and sometimes transistors, not all do, especially the older analogue multimeters that are still in widespread use.However it is still quite easy to perform a simple go / no-go test using the simplest of equipment. 90009 90005 This form of testing is able to detect whether transistor or a diode is operational, and although it can not provide details of the parameters, this is seldom a problem because these components will have been tested at manufacture and it is comparatively rare for the performance to fall to a point where they do not operate in a circuit. 90009 90005 Most failures are catastrophic, rendering the component completely inoperable.These simple multimeter tests are able to detect these problems very quickly and easily. 90009 90005 Diodes of most types can be tested in this way — power rectifier diodes, signal diodes, zener / voltage reference diodes, varactor diodes and many more forms of diode can all be tested. 90009 90019 How to test a diode with a multimeter 90020 90005 The basic diode test is very simple to perform. Just two tests are needed with the multimeter to ensure that the diode works satisfactorily. 90009 90005 The diode test relies on the fact that the diode will only conduct in one direction and not the other.This means that its resistance will be different in one direction to that of the other. 90009 90005 By measuring the resistance in both directions, it is possible to ascertain whether the diode is working, and also which connections are the anode and cathode. 90009 90005 As the actual resistance int he forward direction is dependent upon the voltage, it is not possible to give exact values ​​for the expected forward resistance as the voltage from different meters will be different — it will even be different between different ranges on the meter.90009 90005 90008 90002 90032 … the band on the diode package represents the cathode …. 90033 90003 90009 90036 90005 The method of testing a diode with an analogue meter is quite straightforward. 90009 90039 Step by step instructions: 90040 90041 90042 Set the meter to its ohms range — any range should do, but the middle ohms range if several are available is probably best. 90043 90042 Connect the cathode terminal of the diode to the terminal marked positive on the multimeter, and the anode to the negative or common terminal.90043 90042 Set the meter to read ohms, and a «lowish» reading should be obtained. 90043 90042 Reverse the connections. 90043 90042 This time a high resistance reading should be obtained. 90043 90052 90005 90006 90032 Notes: 90033 90007 90009 90059 90042 In step 3 above the actual reading will depend upon a number of factors. The main thing is that the meter deflects, possibly to half way or more. The variation depends on many items including the battery in the meter, and the range used.The main point to note is that the meter deflects significantly. 90043 90042 When checked in the reverse direction, silicon diodes are unlikely to show any meter deflection whatsoever. Germanium ones that have a much higher level of reverse leakage current may easily show a small deflection if the meter is set to a high ohms range. 90043 90064 90005 This simple analogue multimeter test of a diode is very useful because it gives a very quick indication of whether the diode is basically operational.It can not, however, test more complicated parameters such as the reverse breakdown, etc. 90009 90005 Nevertheless it is an essential test for maintenance and repair. Although it is possible for the diode characteristics to change, this very rarely happens and it is far ore likely that a complete breakdown of the diode occurs, and this would be immediately visible using this test. 90009 90005 Accordingly this type of test is exceedingly useful in a number of areas of electronics test and repair.90009 90071 Diode test using a multimeter 90019 How to test a transistor with a multimeter 90020 90005 The diode test using an analogue multimeter can be extended to give a simple and straightforward confidence check for bipolar transistors. Again the test using a multimeter only provides a confidence check that the bipolar transistor has not blown, but it is still very useful. 90009 90005 As with the diode, the most likely failures result in the destruction of the transistor, rather than a slight degradation in the performance.90009 90005 The test relies on the fact that a bipolar transistor can be considered to comprise of two back to back diodes, and by performing the diode test between the base and collector and the base and emitter of the transistor using an analogue multimeter, most of the basic integrity of the transistor can be ascertained. 90009 90080 Transistor equivalent circuit with diodes for multimeter test. 90005 One further test is required. The transistor should present a high resistance between the collector and emitter with the base left open circuit as there are two back to back diodes.However it is possible for the collector emitter path to be blown and a conduction path created between the collector and the emitter whilst still having a diode function to the base. This also needs to be tested. 90009 90005 It should be noted that a bipolar transistor can not be functionally replicated using two separate diodes because the operation of the transistor depends upon the base which is the junction of the two diodes, being one physical layer, and also very thin. 90009 90039 Step by step instructions: 90040 90005 The instructions are given primarily for an NPN transistor as these are the most common types in use.The variations are shown for PNP varieties — these are indicated in brackets (.. .. ..): 90009 90041 90042 Set the meter to its ohms range — any range should do, but the middle ohms range if several are available is probably best. 90043 90042 Connect the base terminal of the transistor to the terminal marked positive (usually coloured red) on the multimeter 90043 90042 Connect the terminal marked negative or common (usually coloured black) to the collector and measure the resistance.It should read open circuit (there should be a deflection for a PNP transistor). 90043 90042 With the terminal marked positive still connected to the base, repeat the measurement with the positive terminal connected to the emitter. The reading should again read open circuit (the multimeter should deflect for a PNP transistor). 90043 90042 Now reverse the connection to the base of the transistor, this time connecting the negative or common (black) terminal of the analogue test meter to the base of the transistor.90043 90042 Connect the terminal marked positive, first to the collector and measure the resistance. Then take it to the emitter. In both cases the meter should deflect (indicate open circuit for a PNP transistor). 90043 90042 It is next necessary to connect the meter negative or common to the collector and meter positive to the emitter. Check that the meter reads open circuit. (The meter should read open circuit for both NPN and PNP types. 90043 90042 Now reverse the connections so that the meter negative or common is connected to the emitter and meter positive to the collector.Check again that the meter reads open circuit. 90043 90042 If the transistor passes all the tests then it is basically functional and all the junctions are intact. 90043 90052 90005 90006 90032 Notes: 90033 90007 90009 90059 90042 The final checks from collector to emitter ensure that the base has not been «blown through». It is sometimes possible that there is still a diode present between collector and base and the emitter and the base, but the collector and emitter are shorted together.90043 90042 As with the germanium diode, the reverse readings for germanium transistors will not be as good as for silicon transistors. A small level of current is allowable as this results from the presence of minority carriers in the germanium. 90043 90064 90019 Analogue multimeter overview 90020 90005 While most of the multimeters on sale today are digital ones, there are nevertheless many analogue meters still in use. While they may not be the latest in technology, they are still ideal for many uses, and can be used easily for measurements such as the ones above.90009 90125 90005 Although the tests detailed above are aimed at analogue meters, similar ones can be undertaken with digital multimeters, DMMs. 90009 90005 Often digital multimeters may incorporate a specific bipolar transistor test function, and this is very convenient to use. The overall test performance by the specific bipolar transistor test function is often very similar to that mentioned here, although some digital multimeters may give a value for the current gain. 90009 90005 Using the simple test for diodes and transistors is very useful in many service and repair scenarios.Being able to have a good idea of ​​whether a diode or transistor is functional is very useful. As transistor testers are not widely sold, being able to use any multimeter to provide this capability is particularly useful. It is even more convenient because the test is very easy to perform. 90009 90005 90006 More Test Topics: 90007 90008 Data network analyzer Digital Multimeter Frequency counter Oscilloscope Signal generators Spectrum analyzer LCR meter Dip meter, GDO Logic analyzer RF power meter RF signal generator Logic probe Time domain reflectometer Vector network analyzer PXI GPIB Boundary scan / JTAG 90008 90006 90032 Return to Test menu.. . 90033 90007 90009 .90000 How to Test a Car Battery With a Multimeter or Hydrometer 90001 90002 How to Test a Car Battery 90003 90004 You can use a multimeter to find out if your battery has enough charge. With the headlights on, at 80 ° F, there should be a voltage drop of at least 11.8 volts (25% charged), and ideally 12.5 volts, between the positive and negative terminals. You can also use a hydrometer to see if the specific gravity of the liquid inside the battery is between 1.265 and 1.299. 90005 90002 A Guide to Testing, Removing, Cleaning, and Reinstalling Your Battery 90003 90004 This guide tells you how to use a digital multimeter (or voltmeter) or a hydrometer to do some simple tests to find out the condition of your battery.It’ll also show you how to remove, clean, and reinstall your battery. 90005 90004 If you are having trouble starting your car, or trouble keeping your battery charged, your problem may be in the starting or charging system, but it is often in the battery itself. A worn-out battery, corroded terminals, acid buildup, and battery case damage are among the main culprits behind starting problems and charging system problems. 90005 90002 How to Find Out if Your Car Battery Is Charged 90003 90004 Here are two methods you can use to learn the state of your battery using simple diagnostic tools.90005 90004 The first method is to use a digital multimeter to quickly check if your battery has enough charge to start your car. This is the best way on so-called maintenance-free batteries, which do not have removable caps. Some maintenance-free batteries come with a charge indicator, a display on the battery top that tells you if the battery is fully charged (green dot), in need of a charge (no color visible), or faulty (yellow dot). 90005 90004 The second method uses a hydrometer. Unlike the digital multimeter, the hydrometer can reveal not only the state of charge of your battery, but also its overall health.You’ll know if your battery has failed. But you can only use this tool on batteries with removable caps. You can buy an inexpensive hydrometer at most auto parts stores or online. 90005 90002 90021 1. How to Test Your Car Battery’s Charge Using a Multimeter 90022 90003 90004 You can use your digital multimeter to find out in a minute whether your car battery has enough juice to get your car going. 90005 90026 90027 90004 90029 First, set your voltmeter to 20 DC volts. See the video below.90005 90031 90027 90004 90029 Touch the negative (black) battery terminal with the negative (black) meter probe. 90029 90005 90031 90027 90004 Touch the positive (red) battery terminal with the positive (red) meter probe. 90005 90031 90027 90004 90029 Ask an assistant to turn on the headlights to provide the battery with a light load. 90029 90005 90031 90027 90004 Check your voltmeter reading. At a temperature of about 80 ° F (26.6 ° C): 90029 90005 90031 90053 90004 If you got a low reading, slow charge your battery to improve the chemical reaction of the battery and repeat the test.If your reading does not go higher, replace the battery. 90005 90002 2. How to Test Your Car Battery Using a Hydrometer 90003 90004 This test is also called an electrolyte gravity test. It will tell you whether your battery is fully charged, undercharged, or even faulty. 90005 90004 For best results, use a hydrometer with a built-in thermometer. Some hydrometers are self-adjusting; other hydrometers come with a conversion table to adjust your reading when performing the test at different ambient temperatures.90005 90004 When doing this test, wear acid-resistant gloves and goggles. 90005 90064 90021 Using the Hydrometer to Test the Battery Fluid 90066 90022 90068 90026 90027 90029 Remove the caps from the top of the battery. 90031 90027 90029 Submerge the tip of the hydrometer into the first cell of the battery and squeeze the hydrometer bulb. 90031 90027 90029 Release the bulb to allow electrolyte to enter the hydrometer needle. 90031 90027 90029 Read the electrolyte specific gravity as indicated in the instructions on the tool’s package.90031 90027 90029 Make a note of your reading and perform the same test on the rest of the cells. 90031 90027 90029 Compare your results to those of your tool manufacturer’s instructions. 90031 90053 90004 Basically, if your readings fall between 1.265 and 1.299, your battery is charged. When your readings fall below 1.265, your battery is undercharged. In most cases, a slow or trickle charge will help restore the charge and improve the chemical reaction in the battery. However, a difference of 25 to 50 points or more (a point equals 0.001), between any of your readings indicates that the battery is sulfated and you need to replace it. 90005 90002 How to Check the Battery Terminals Using a Multimeter 90003 90004 Dirty, corroded, or loose battery terminals will lead to hard-to-start or no-start issues, and are one of the main reasons people think they have a «dead battery. » Sometimes these types of problems are hard to spot with a simple visual inspection. 90005 90004 Here, you’ll use a voltmeter (or a multimeter set to voltage) to check your battery terminals for voltage drop, so that you can understand the state of your battery connections.90005 90026 90027 90029 First, disable the ignition system. Do this by temporarily disconnecting the ignition coil or removing the fuel pump fuse or relay (check your car owner’s manual or your vehicle repair manual to locate the coil or fuse, if necessary). This will prevent your engine from starting. 90031 90027 90029 With your meter’s red probe, touch the positive battery post. Now, touch your meter’s black probe to the cable terminal connecting to the same battery post. 90031 90027 90029 Ask an assistant to crank the engine.If your meter registers over 0.5 volts you need to clean or check the physical condition of the battery post and terminals. 90031 90027 90029 Now, test the other battery terminal. This time, though, with your meter’s black probe, touch the negative battery post. Now, touch your meter’s red probe to the cable terminal connecting to the same battery post. Ask your assistant to crank the engine and check the voltage reading on your meter. If it is more than 0.5 volts, you need to check your battery terminal for damage, or clean it.90031 90053 90002 How to Do a Leak Test on the Battery Cover Using a Multimeter 90003 90004 A buildup of deposits on the battery cover is a common cause of what seems to be a «dead» battery. As dirt and acid mix and accumulate across the top and terminals, the charge slowly begins to leak. To check whether your battery has reached the leaking point, use a multimeter. 90005 90115 90027 Set your voltmeter to a low setting on the voltage scale. 90031 90027 Turn on the voltmeter. 90031 90027 Then touch the battery negative terminal (-) with the black probe from your meter, and touch the dirty battery cover with the red probe.90031 90122 90004 If your meter registers even a small amount of voltage, buildup has begun to leak battery power. Head to the section below on «How to Clean a Car Battery» to remove the leak. 90005 90004 If you get zero volts reading from your meter but you still suspect that some electrical device is draining power from your battery-a «parasitic draw» -check this other article, Car Battery Drain, to locate the circuit and the device discharging your battery . 90005 90002 How to Visually Inspect the Battery Case and Cables 90003 90004 Now it’s time to check the physical condition of your battery case.A damaged battery case can not only prevent the battery from working properly, but will eventually kill it. To check the battery, you’ll need to remove it from your vehicle. 90005 90026 90027 90029 First, disconnect the battery cables starting with the ground terminal and then the positive terminal. Now, unscrew the hold-down mechanism to remove the battery from the tray. 90031 90027 90029 Make sure the hold-down mechanism works. If there’s missing hardware, replace it. This hardware prevents the battery from bouncing and getting damaged when the vehicle is moving.90031 90027 90029 Place the battery on a workbench or similar surface. Carefully examine the battery case for potential damage. Check for a bulging side or cover, cracks around the case, or damaged terminal posts. If your battery is damaged in any way, replace it. 90031 90027 90029 Overcharging and internal short circuits will cause a battery to swell as the acid turns to gas. So if you find signs of bulging, check the charging system as well. 90031 90027 90029 Now, check the battery cables.Check for frayed, cracked, or worn insulation around the cables and the condition of the cable threads. Replace them as necessary. 90031 90053 90002 How to Clean a Car Battery 90003 90064 90021 1. Cleaning the Battery Case 90022 90068 90004 You can use a simple procedure to clean the battery case. For this, you’ll need to prepare a mixture of 8 ounces of warm water and one tablespoon of baking soda. This will neutralize acid and help lift up dirt off the battery case and terminals. 90005 90004 Put on your goggles and rubber gloves and, using a soft brush, apply the solution across the battery top and around the sides of the case.If your battery uses cell caps (maintenance type batteries), do not let the mixture seep under the caps and mix with the electrolyte inside. 90005 90004 Wipe the solution using a clean rag. Continue applying the cleaning solution until you see no signs of buildup. 90005 90064 90021 2. Cleaning the Battery Terminals 90022 90068 90004 Just as you did with the battery case, remove dirt and corrosion off the battery terminals using the baking soda and water solution. 90005 90004 To make your task easier, pour the mixture into a foam cup or similar disposable cup and dip the battery terminal in it for one or two minutes.Then use a battery-post cleaning tool to finish removing the corrosion from the terminals. Repeat the procedure until you see both terminals free of corrosion. 90005 90064 90021 3. Cleaning the Battery Tray 90022 90068 90004 Inspect the condition of the battery tray. Make sure it has no missing screws, no cracks or missing pieces, and no signs of corrosion. If necessary, use the same solution to remove dirt and corrosion from the tray. 90005 90002 Reinstalling the Battery 90003 90004 After cleaning the battery case, terminals and tray, reinstall the battery.90005 90026 90027 90029 Carefully place the battery on its tray. 90031 90027 90029 Secure the battery to the tray using the hold-down mechanism. 90031 90027 90029 Connect the battery terminals. This time start with the positive terminal and connect the negative or ground terminal last. 90031 90027 90029 After connecting the terminals, spread a thin layer of petroleum jelly around the top of the terminals and posts. This inhibits corrosion buildup around the terminals. 90031 90053 90002 What Next? 90003 90004 If your tests showed your battery to be in good health, you may have a problem with the starting or charging system.This other article on Troubleshooting Car Starter Problems shows you how to do some quick tests without using tools. 90005 90004 Once you know how to check your car battery for problems, you’ll service the battery faster next time around. And servicing your battery regularly goes a long way. You can make sure your battery provides all the necessary power to the starting system, ignition system and other important electrical circuits as necessary, especially during the cold months. Even more, with a little maintenance you’ll help prolong the service life of your battery and stretch your car maintenance budget.90005 .90000 How To Test Electrical & Electronics Components with Multimeter? 90001 90002 90003 How To Test Electrical & Electronics Components with Multimeter? 90004 90005 90006 90003 Troubleshooting with Multimeter 90004 90009 90010 We all know the rule and importance of «Troubleshooting» in Electrical and Electronics Engineering. Most EE components and elements used in Electrical and Electronics equipments, devices and instruments are common in their functions and operations. 90011 90010 To be a good analyzer and troubleshooter, you must know the following basic techniques and has good skills in Electrical and Electronics troubleshooting, design and analyzing electric / electronic circuits.For this purpose, we have started a multimerer tutorial where we will use DMM (Digital Multimeter) and AVO Meter (Ampere-Voltage-Resistance Meter) or Multimeter (Digital / Analog) to test different electrical / electronics devices, instruments and components to find their terminals and condition such as are are they short, open, good or faulty. 90011 90010 In this basic multimeter tutorial, We will use digital and analog multimeter to check the following electrical and electronic components, devices, tools and instruments: 90015 90011 90017 90018 Cable and Wires 90019 90018 Switch / Push Buttons 90019 90018 Fuse 90019 90018 Capacitors & Inductors 90019 90018 Resistors & Burnt resistors 90015 90019 90018 Diodes and LED 90019 90018 Battery 90019 90018 Transistors 90019 90018 Relays 90019 90037 90010 90039 90039 90011 90010 In troubleshooting, we use different kinds of basic Electrical and Electronics Engineering Tools but the main and important tool is Multimeter.Now we will check the above mentioned components and devices with this tool one by one. 90011 90006 90003 Cable and Wires 90004 90009 90010 To check if the cable and wires are in good condition or broken before sizing the proper cable & wire for Electrical Wiring installation, we perform the continuity test. For this purpose, take AVO meter (or Digital Multimeter) and select «Resistance» (in AVO meter … Rotate the knob to the «Ω» or Resistance). 90011 90010 Now connect both terminals, i.e. both naked ends of the cable / wire with the AVO or Digital Multimeter Terminals. If the meter reading shown «0 Ω», it means Cable / Wire is in «Good Condition». On the other hand, if meter reading is «Infinite», it shows the cable / wire may be defected or broken. So you need to replace it with a new one. 90011 90006 90003 Switch / Push Buttons 90004 90009 90010 Use the same method (mentioned above for checking the cable and wires) … to perform this method correctly, you will need to apply this method in both cases (ON & OFF positions) on switches and push buttons … In other words, first apply this method on switches / push buttons and then «Push» the push button and perform the same method again.90011 90010 At first attempt, if meter reading is «Zero» and in the second attempt, the meter reading is infinite, it means Switch / Push button is in good condition. If Multimeter reading is «Zero» or «infinite» in both attempts, it means switch is in short circuit or continuity connection is broken and you should replace it with a new one. 90011 90006 90003 Fuse 90004 90009 90010 To verify Fuse condition, i.e. is «Fuse» in good condition or damaged? … We perform the same method I.e. continuity test as mentioned above.In short, if the meter reading is «Zero» it means Fuse is in good condition. If Multimeter reading is infinite, it means Fuse continuity may be broken or blown. So you should replace it with a new one immediately. 90011 90006 90067 90067 90003 Capacitor 90004 90009 90010 We have already discussed the topic «How to Check a Capacitor with Digital (Multimeter) and Analog (AVO Meter), By Four (6) Methods with pictorial views. 90011 90010 In this tutorial, you can check with Digital Multimeter or AVO meter if the Capacitor is Good, Short or Open? 90011 90006 90003 Diode & LED 90004 90009 90010 We have updated a detailed post about «How to Test a Diode using Digital & Analog Multimeter» by four methods.In this multimeter tutorial, we have shown different things about diode such as using diode mode in DMM and resistance mode in DMM and AMM to identify the terminals of Diode, LED and Zener diode. In addition, you may also check if the diode is good, bad, short or open. 90011 90006 90003 Transistor 90004 90009 90010 In another detailed multimeter tutorial about «How to Check a Transistor by Multimeter (DMM + AVO)» you may find the Base, Collector and Emitter of a transistor by using Digital and analog multimeter.Also, There is an easy method to remember the direction of NPN and PNP transistors. In short, in this tutorial, You will be able to use the multimeter in resisatnce mode (Digital + Analog multimeter) or hFE / Beta mode (Only DMM) to test a transistor if is it good, faulty, short or open. 90011 90006 90003 Battery 90004 90009 90010 In the basic test meter tutorial about «How to test a battery with Test meter?» you will be able to find if the battery is in good condition, charged, need to be charge, low charge / current, high charge / current or is it faulty and need to be replaced with new one.90011 90006 90003 Resistor & Burnt Resistors 90015 90004 90009 90010 To check if the Resistor is in good condition or broken, we use a multimeter. For this purpose, take AVO meter (or Digital Multimeter) and select «Resistance» (in AVO meter … Rotate the knob to the «Ω» or Resistance). Now connect both ends of resistor with the AVO or Digital Multimeter Terminals. If the meter reading shows the exact value of resistance or with a percentage tolerance, it means Resistor in «Good Condition».90011 90010 For Example, 1kΩ = 1000Ω with a 5% tolerance will show the reading near about 950Ω to 1050Ω. On the other hand, if meter reading is «Infinite», it shows the Resistor may be defected or broken and open. So you need to replace it with a new one (exact value). 90011 90010 Good to know: 90011 90010 You can also check the value of a burnt resistor with Digital or analog multimer by the following three handy methods. 90011 90010 Related Post: How to find The value of Burnt Resistor (By three handy Methods) 90011 90006 Relay Coils & SSR Relay 90009 90010 To test an SSR (Solid state relay) and electromechanical relay coils by using multimter, You will have to follow the detailed and step by step guide about «How to Test a Relay? Checking SSR & Coil Relays «90011 90006 90003 General Precaution 90004 90009 90017 90018 Disconnect the power source before checking, servicing, repairing or installing electrical equipments and devices.90019 90018 Always, Select the higher value in Digital or analog Multimeter, and then, gradually reduce it to the proper valve. 90019 90018 Never try to work on electricity without proper guidance and care 90019 90018 Read all instruction and cautions and follow them strictly. 90019 90018 The author will not be liable for any losses, injuries, or damages from the display or use of this information or try any circuit in the wrong format so please! Be careful because it’s all about electricity and electricity is too dangerous 90019 90037 90010 90130 Note: This basic multimeter tutorial has to be updated with new testing method with DMM + AMM … Stay tune.90131 90011 90010 Related Tutorials: 90011.