On the electronic circuits, you can see that two diodes are connected in counter-parallel.This can be seen in the high frequency amplifier circuit of the radio receiver.Why are they doing this?
To understand and show this, I took two 1n4148 diodes and connected them in parallel, as shown in the diagram.The source of alternating voltage is the motor, which is located in microwave ovens.This motor can produce an alternating voltage of up to 200-300 volts if you twist its rotor
As you can see in the photo, if you do not connect the diodes in parallel to the electric motor, it outputs a voltage of 19 Volts, this is with a small spin of the rotor
With the diodes that I connected in parallel to the electric motor, the voltage will be no more than 0.7 Volts.Why did this happen?
The thing is that at a voltage higher than about 0.6-0.7 Volts, silicon diodes open and thereby limit the voltage, which will be higher than 0.6-0.7 Volts.Moreover, each diode opens on its own half-wave of a sine wave.
In radios, in order not to disable its input stage, diodes limit the signal coming from the antenna.
Naturally, the current and voltage of the signal should be less than what the diodes are designed for.
