Free circuit schematics - wiparat.com

Read more
Other Link
Pulse width modulation using IC 555
Car Temperature Gauge by IC CA3162 + CA3161
Temperature Monitor with IC LM741 or LM301

IC1 astable gives a fixed square wave at pin 3, C1 and R1 derive uS trigger pulses from IC1 and this will trigger IC2 monostable or single shot, the voltage at pin 5 of IC2 will change the pulse width output of IC2, to get it working all the three RC combinations have to be [...]

Often, people attempt to control DC motors with a variable resistor or variable resistor connected to a transistor. While the latter approach works well, it generates heat and hence wastes power. This simple pulse width modulation DC motor control eliminates these problems. It controls the motor speed by driving the motor with short pulses.
Read more [...]