I plan to make an electric screwdriver and naturally need to adjust the speed. I found the NE555 speed governor on the Internet. Immediately I felt that NE555 was really almighty. I still had a few tablets of 555 on hand, but some netizens reported that the MOS tube was very hot! After some discussion, two resistors were changed. It is true that the fever is not so serious. I do not have a heat sink. The circuit diagram is changed, and it is posted at the end, the process is gone, because it is quite simple ~
50K adjustable resistor
NE555 chip, here to say, if you need to control higher voltages such as 24V.
You need 7812 to step down to power the 555, so the motor should not be connected to the same VCC!
Because the 555 input voltage is 4.5V-16V.
IRF540N MOS tube close-up, there is really no heat sink, basically does not generate heat, and I have seen some people make a fuss to control the 775 motor with IGBT, I think it is a waste. Of course, several 1N4148 diodes and 1N4007 diodes are also needed.
The back is soldered a bit rough.
Terminals, the two on the left are for power supply, and the two on the right are for motor.
The length is only 70MM. Without the adjustable resistance, it is only 55MM.
Looking at the finished product, there is only a small piece.
Finally, paste the circuit diagram, which is drawn with AD9. It is not easy to forgive me, I did not draw the PCB.