Mahjong machine's electronic part is very simple, with a domestic single-chip microcomputer as the core and some complicated mechanical transmission parts. Three times five divided by two, we took out our protagonist: permanent magnet motor.
I found a very long screw (20cm), a turntable and a crank, so a simple AC motor was completed. Preliminary test with electric pen showed that the voltage was above 200V V V. At this time, I was a little hungry, so I looked at my roommate, damn it! I fell asleep and looked at my watch. It's past 23:00, and now I remember that I haven't had lunch yet. ..................
How to make a simple AC motor?
The next day, I woke up early in the morning and threw away the generator. At present, the motor still generates alternating current with high voltage. We have to find a way to get a voltage stabilizing module. The first idea is to start with the charger, dismantle a mobile phone charger, look at the main power devices and circuit structures, and easily find the corresponding schematic diagram:
This diagram is too simple. We must revise it and check the related data sheets. It is found that the driving current of Q 1 1300 1 is only about 500mA, which is relatively weak. So I went to find a 13005 driver tube, and the driving current was as high as 1~2A. Also, the rectification efficiency of this circuit is too low. There is only one rectifier DIN4007, and a bridge rectifier is decisively found to replace it. In addition, I was worried that the voltage fluctuation of the generator was too big for the circuit, so I added a π-type filter circuit. Haha, the current circuit is just right. The following are rectifier voltage stabilizing plates:
The generator DIY has come to an end, and now I dare not charge the mobile phone because the output voltage characteristics have not been verified. So I rode my little donkey straight to the company laboratory. I came to the company because it was Sunday and only a few people were there. I called a senior brother for help and tested it: the voltage behind the bridge rectifier was 400V when it was empty and dropped to 200V when it was loaded. The USB output port is stable at 5.53V to 5.6V, and the fluctuation does not exceed 0.1V. This performance is so good that I am surprised!