Please give me some advice, brothers and sisters.

刘兴光

Please give me some advice, brothers and sisters. [Copy link]

I am a newbie, please give me some advice, This is the circuit diagram of the 11th issue of the 2010 Electronic Newsletter. When I was adjusting it, I found that the potentiometer produced a large spark. Why? This is a voltage regulation circuit! Because I didn't buy a 470K potentiometer, I used a 250K one instead. Please give me some advice.

zcgzanne

The phenomenon of "the potentiometer produces a large spark" is basically judged as overcurrent (exceeding the rated power)

刘兴光

Which potentiometer should I use?

刘兴光

Which potentiometer should I use?

08221034

Sparks may be caused by poor contact of the potentiometer, but in many cases it is normal. If you are not sure whether the components can be replaced during production, it is recommended to find the same circuit and then produce it. High voltage is more dangerous

刘兴光

Thanks for your advice:handshake

lixiaohai8211

Using 250K instead of 470k will produce a lot of current difference

wangjiafu1985

A very common circuit for adjusting the phase angle to adjust the output power. The potentiometer forms a phase shift circuit with the capacitor C. The phase shift triggers the thyristor. Adjusting the potentiometer adjusts the trigger phase, thereby achieving the purpose of adjusting the output power. However, the spark of the potentiometer is mainly due to the problem of the potentiometer. Replace it with a good potentiometer.

leang521

No problem, it can be used normally. The spark is only caused by the quality problem of the potentiometer.

刘兴光

Thank you for your advice:handshake :pleased:

simonprince

[quote]Originally posted by wangjiafu1985 on 2010-6-1 21:51 A very common circuit for adjusting the phase angle to adjust the output power. The potentiometer forms a phase shift circuit with the capacitor C. The phase shift triggers the thyristor. Adjusting the potentiometer adjusts the trigger phase, thereby achieving the purpose of adjusting the output power. Is it the role of the delayed conduction thyristor: L

leang521

Originally posted by simonprince on 2010-6-2 08:48 [quote]Originally posted by wangjiafu1985 on 2010-6-1 21:51 A very common circuit for adjusting the phase angle to adjust the output power. The potentiometer forms a phase shift circuit with the capacitor C. The phase shift triggers the thyristor, and adjusting the potential...

Adjusting the conduction angle of the thyristor controls the power

yealien

Use a higher power one. This will happen when a general potentiometer is connected to AC.

zhutx

There seems to be something wrong with the circuit. The two points connected to the soldering iron should be short-circuited. The soldering iron should be connected in series in the 220V power supply circuit. After the thyristor is triggered, the voltage of the control part should be adjusted to zero.

刘兴光

When I was adjusting it, I found that the voltage didn't change at all, and there were big sparks when adjusting the potentiometer [ This post was last edited by Liu Xingguang on 2010-6-2 15:20 ]

zhutx

Using the original circuit may damage the bidirectional trigger diode, potentiometer and even thyristor, so check whether the components are damaged. It should be fine to connect as shown below.

刘兴光

我試下

刘兴光

I'll try

刘兴光

I tried your circuit and it seems to have some problems. Shouldn't the 0.68uF/400v capacitor withstand a very high voltage? When adjusting the potentiometer, the capacitor makes a loud noise and the voltage doesn't change :time:

刘兴光

However, I didn't have a 470K potentiometer, so I used a 1M potentiometer instead.