Capacitor Buck Regulator Power Supply Circuit Diagram

If the capacity of capacitor C1 is doubled, the output current can be nearly doubled, but it cannot be too large. If the output ripple is large, an analog voltage regulator such as 7805/317 can be connected behind it. Changing the value of R3 can change Output voltage. The marked output current is the maximum output current. The triac B1 can be 1A.

This power supply can be short-circuited. If you can ensure that the capacitor C1 is connected to the live wire, you can touch it with your hands. Originally, this power supply was provided for small electrical appliances that people do not touch. As long as the non-polar capacitor C1 has enough voltage resistance, there is no problem in long-term use. From the principle Technically speaking, this is a parallel voltage stabilizing circuit with an input voltage of 220V. The voltage drops across C1. If the output current is large, the capacity of C1 can be increased. I once increased it to 2UF and it can be used normally. I have also tested 4UF. , when pulling out and plugging in the plug, the spark was too big, so I stopped using it. I used the picture 1, and the thyristor and 431 were not damaged. In fact, since E1 is 470 times larger than C1, even at the moment of switching on, the AC The peak value is more than 300 volts, and there will be no high voltage on E1. The power is easy to calculate. The capacitive reactance of a 1UF capacitor to 50HZ is 3.15k. The output current is estimated: 200V/3000 ohms, and the current is about 60MA. If it is half-wave rectified , the current is only half. About 30MA.