See: 555 PWM DC LED dimmer circuit in 12V source. For a lot of loads even control the speed motor. Nearly with loss and high performance
All controller, motor speed driver,switches,timer,sensor,and more : Timer switches • DC motor speed control • Delay timers • Light switchs • SCR controls • Light dimmers • Infrared remote control system • and more…
SEE DIY compressor time delay circuit. Protect your compressor when power outage and Electrical fluctuations. Using normal parts and cheap.
You finish PWM signal with Arduino control solenoid valve. You should use solenoid coil driver circuit. Good choice. 2 MOSFET and a few parts
Simple Key code lock switch circuit using IC-4017 digital, uses 10 switch bottom to control output by Relay. No microcontroller so easier and cheaper!
This is timer circuit uses a 555 IC timer. it small,compact,portable. For the snooze alarm by buzzer when some 5 to 30 minutes. It make easy with pcb layout
Many how to make simple touch switch circuit project. To build easy. Using transistor and IC like 555 timer, 4011 CMOS, flip-flop IC.
It will prevent the speaker from too over high power output may speaker damaged it use transistor and relay cut off as safe.