Category «Control and Monitoring»

Series-Wound Direction And Speed Motor Control

This is a motor controller circuit that  control the speed  and direction of series-wound Motors. This circuit employs silicon controlled rectifiers (SCR) Q1-Q4, that are triggered in diagonal pairs. The switch St is used to control which pair is turned on because either coupling transformer T2  or coupling transformer T1 is connected to a pulsing …

General Purpose Alarm Circuit for Resistive Sensor

When the resistance value of a temperature, light, pressure,  or any other resistive sensors  Rs drops below a certain point  (adjusted by a preset potentiometer),  the SCR (silicon controlled switch) will be triggered. The sensor (Rs) and the potentiometer placement can be interchanged to get opposite action, where the SCR need to be triggered  at …

Mixer or Sewing Machine Motor Speed Control

It will be effective to use simple half wave motor speed control with small universal  ac/dc motors. Two amps RMS is the maximum current capability. The control gives excellent torque characteristics to the motor because speed dependent feedback is provided, even at low rotation speeds. By closing switch S1, thus bypassing the SCR, we can …