SEE DIY compressor time delay circuit. Protect your compressor when power outage and Electrical fluctuations. Using normal parts and cheap.
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…
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!
It will prevent the speaker from too over high power output may speaker damaged it use transistor and relay cut off as safe.
The Simple long duration timer circuit using OP-AMP, If build the RC timer only that long time delay we need too many resistors and capacitors may be error [...]