Definition of diode:
It is an electronic component that allows current to pass in one direction only, regardless of the value of the current passing with forward bias from the positive terminal (anode) to the negative terminal (cathode). It is used in mobile devices in the lighting and charging circuit (D).
Types of diodes
1) Zener diode stabilizes the current at a specific voltage and discharges excess current to ground like a charging zener (DZ).
2) Light-emitting diode (LED ) that lights up when current passes through it .
3) Zener diode: A diode that operates in reverse bias at a certain voltage, where current passes from the negative terminal (cathode) to the positive terminal (anode).
1) In lighting circuits, it can cause flickering of the light when there is a leak, in which case it gives a different reading from both sides and must be replaced. If it is damaged, the lighting circuit must be disconnected permanently.
2) In the charging circuits , if it is damaged, the charging process stops, and if there is a filter (leak), it leads to the charging voltage leaking and the required voltage does not reach the charging IC to do its job, thus causing a malfunction in the charging process.
Diode mounting direction (unit)
The diode is polarized and if damaged, it must be replaced with one of the same size. The diode's orientation should be taken into account during installation. A thin line is placed on one end of the diode to indicate the installation direction. If the diode is reversed during replacement, it will prevent current from flowing and the circuit will stop working.
Disconnect the power supply from the device by removing the battery or power supply and setting the multimeter to the buzzer (diode) position . Then place the multimeter leads on the diode leads once and reverse the leads again. The measurement result will be as follows:
1) The diode gives a bell in both cases and is damaged.
2) The diode gives the same reading in both cases without a bell, so it is damaged.
3) The diode gives a reading in both cases and is damaged.
4) The diode gives a reading on one side and infinity on the other side, which is fine.
5) The diode gives a reading on one side different from the other side. The diode has a filter (leakage).
It can be checked while it is in the circuit. When the two ends of the ohmmeter are placed after setting it to BUZZER, we find that it gives a reading in one direction, and when the two ends of the ohmmeter are reversed, it does not give a reading or gives a lower reading, and thus it is sound. As for the LED, it lights up in one direction, and when the two ends of the ohmmeter are reversed, it does not light up.