Main function:

Suppress the transient surge current when the power amplifier is turned on. Due to the large transformer power of the Class A and high-power power amplifiers, the extremely low load impedance and the large capacity of the power supply filter capacitor, the current is too large at the moment the power amplifier is turned on, which is very easy to damage the rectifier bridge and damage the filter. capacitance.

 

Working principle:

Turn on the AC 110V or 220V IN power supply, control one of the 30A relays to pull in, so that the thermistor is connected in series, after 2-3 seconds, the main 30A relay is turned on, and the entire AC 110V or 220V OUT power supply is turned on.

 

Common problem:

Question: The 0.01UF capacitor is a spark-extinguishing capacitor, which is separately installed in the main relay and switch. Some friends will say that when the board is not connected to the load, use a multimeter to measure the 220V voltage at the output terminal when the switch is not turned on;

Answer: Since the internal resistance of the multimeter is as high as tens of M, this is an induced voltage. The reason is that the mains is coupled through a 0.01UF capacitor, and it disappears when the load is connected. The situation is the same as the principle of static electricity when the mainframe of your home computer is not connected to the ground wire.
 

PCB Size: 105mm*70mm

 

NOTE: This is a finished board that is welded and tested OK.

 

This board has two voltage versions. Please choose the voltage version based on the voltage in your country:

◆ The AC 110V version is usually used in AC 100-120V countries.

◆ The AC 220V version is usually used in AC 220-240V countries.