Diode Function And How To Measure It

Diode function and how to measure it – Diode (Diode) is an Active Electronic Component made of semiconductor material and has a function to conduct electric current in one direction but inhibit electric current from the opposite direction. Therefore, diodes are often used as rectifiers in electronic circuits. Diodes generally have 2 electrodes (terminals) namely the anode (+) and cathode (-) and have a working principle based on semiconductor pin junction technology, which is to allow current to flow from the p-type side (anode) to the n-type side (cathode). but cannot flow in the opposite direction.

Diode function and its types

Based on the function of the diode, the diode can be divided into several types, including:

• Rectifier Diode (Ordinary Diode or Diode Bridge) which functions as a rectifier of AC current to DC current.
•  Zener diode which serves as a safety circuit and also as a voltage stabilizer.
•  LED diodes that function as indicator lights or lighting lamps
•  Photo diode which functions as a light sensor
• Schottky diode which serves as controller

Symbol Of Diode

The picture below shows that the diode is an active electronic component consisting of 2 types of materials, namely p-type and n-type materials:

Diode Working Principle

To be able to clarify the working principle of diodes in delivering and inhibiting the flow of electric current, below is a basic circuit example of the installation and use of diodes in an electronic circuit.

read also Definition of Active and Passive Electronic Components 

How to Measure Diodes with a Multimeter

To find out whether a diode can work properly according to its function, it is necessary to measure the diode using a multimeter (AVO meter).

How to Measure Diodes using an Analog Multimeter

1. Set the Switch Position at OHM Position (Ω) x1k or x100
2. Connect the Red Probe to the Cathode Terminal (ring mark)
3. Connect the Black Probe to the Anode Terminal.
4. Read the measurement results on the Multimeter Display
5. The needle on the Multimeter Display must move to the right
6. Turn the Red Probe to the Anode Terminal and the Black Probe to the Cathode Terminal (ring mark).
7. Read the measurement results on the Multimeter Display
8. The needle must not move.

**If the needle moves, the diode is probably damaged.

How to Measure Diodes using a Digital Multimeter

In general, Digital Multimeters provide measurements for Diode Functions, if not, then we can also measure Diodes with Ohm Functions on Digital Multimeters.

How to Measure Diodes using a Digital Multimeter

(Ohm/Ohmmeter Function)

1. Set the Switch Position to OHM Position (Ω)
2. Connect the Black Probe to the Cathode Terminal (ring mark)
3. Connect the Red Probe to the Anode Terminal.
4. Read the measurement results on the Multimeter Display
5. The display must show a certain value (eg 0.64MOhm)
6. Turn the Black Probe to the Anode Terminal and the Red Probe to the Cathode
7. Read the measurement results on the Multimeter Display
8. The resistance value is Infinity (infinity) or Open Circuit.

**If there is a certain value, then the diode is probably damaged.

How to Measure Diodes using a Digital Multimeter

(Using Diode Function)

1. Adjustable the Switch Position on the Diode Position
2. Connect the Black Probe to the Cathode Terminal (ring mark)
3. Connect the Red Probe to the Anode Terminal.
4. Read the measurement results on the Multimeter Display
5. The display must show a certain value (For example 0.42 V)
6. Turn the Black Probe to the Anode Terminal and the Red Probe to the Cathode
7. Read the measurement results on the Multimeter Display
8. There is no voltage value on the Multimeter Display.

**If there is a certain value, then the diode is probably damaged.

 

Vital Records:

The thing to note here is how to measure diodes using an analog multimeter and a digital multimeter is reversed. Pay attention to the position of the Red Probe (+) and the Black Probe (-).

The measurement methods mentioned above can also be used to determine which terminal is cathode and which terminal is anode if the ring mark printed on the diode can no longer be seen or is erased (lost).