How to Test an LED with an Analog Multimeter

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LEDs are light emitting diodes that are incredibly small. That is why they are used in so many different types of electronics. Today, it can be difficult to find an LED light that is not in some  electronic device. LEDs are everywhere, from traffic lights to cell phones. 

LED is short for Light Emitting Diode. As the name suggests, it is a device that emits light when current passes through it. 

LEDs are often used in signal lights, but  are increasingly being used in flashlights, street lights, and just about anywhere else that requires a signal light (or  flashlight). However, LEDs are not without their disadvantages either. 

For example, they can be expensive – especially if you need a lot of them. They can also be difficult to control – perhaps they  need to be handled individually by a circuit. Finally, they can have a very narrow field of view – meaning you have to look directly at them to see them.  

The Importance of LEDs

LEDs are so common nowadays. If you have a device, it probably has an LED light. Although we have become so used to them, it is  easy to forget that their only function is to give us visual feedback. 

It can be as simple as flashing when we turn on the display of a device  or  digital meter.  The importance of the LED is that it is a semiconductor light source that can be controlled by a microprocessor, unlike  older light sources such as incandescent  or fluorescent lamps. 

LEDs consume less energy and are much more reliable than incandescent bulbs. LED lights are more efficient than fluorescent lights and more reliable in extreme temperatures. 

Testing the LED 

Testing a LED with an analog multimeter is a three-step process: 

  1. First, you must set the multimeter to measure resistance; if the meter does not have a particular resistance setting, press and hold  the setting button to change modes until you find the resistance. 
  2. Then you must connect the first lead(black) of the multimeter to the negative terminal of the battery. 
  3. Finally, you  connect the other wire(red) to the positive terminal of the battery, which causes the multimeter to register the voltage on the negative terminal. 

Understanding and Testing the Analog Multimeter on the LED 

Analog multimeter (also called a VOM or volt-ohm meter) is a meter used in electrical work such as measuring voltage, current, and resistance. 

Analog multimeters do not provide digital readings, but  have moving needles. This makes them very easy to read. Analog multimeters have a number of features that make them quite versatile. 

The first step in using an analog multimeter is to understand the different functions and how to use them. 

An analog multimeter is a device used to measure voltage, current, and resistance. Most devices have meters that can  measure more than one of these functions. There are four basic forms of analog multimeter – DMM, DVM, and oscilloscope.

The analog multimeter is used to test electrical circuits by measuring  electrical quantities. An analog multimeter can measure AC or DC voltage, AC or DC current, resistance, capacitance, frequency, temperature, and duty cycle. 

Analog multimeters are suitable for testing resistors, capacitors, fuses, transistors, diodes and voltage. They can also measure frequency, but usually only up to about 10 kHz. with a 10 MHz signal generator. 

These are not required for IC testing. To test the circuit, simply move the black wire to the COM terminal and the red  to the voltage, resistance or current terminal. Then read the value on the display.

Knowing how to use an analog multimeter is an important skill for anyone who works with electronics. While digital multimeters can cost hundreds of dollars, analog meters can be picked up for a couple of bucks, and they work just as well. 

You can test a simple circuit with either a digital or an analog meter, but a digital meter lets you read values instantly. In contrast, an analog meter shows you what’s going on by displaying a needle that moves across a scale. You can test your device’s voltage, and you can see if it’s receiving current or if it’s working at all.

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