09-03-2017, 04:26 PM
The UJT, the capacitor and the resistors form an oscillator that supplies an AC voltage to the SCR door. From my understanding, the SCR does not shut down when the gate pulse becomes zero. It will only turn off when a negative pulse is applied. However, in this situation, the gate pulse is fed by the UJT Base1 shown in the diagram. The Base1 pulse is only from the 0V level to a certain positive level voltage (without negative voltage level).
This is DC 12V motor speed motor controller circuit. As the SCR DC motor speed control circuit using IC-CMOS. You can adjust the rotation speed of the spindle motor from 5-60 cycles per minute. The work of the circuit, the IC1- (CD4081) is gate door type ic. Accepts the bridge diode voltage BD1. But there is no filter to regulate the current. The other on pin 2. The VR1, C1 and R1 is a phase change or delay time, the voltage from pin 3 to the triggers pin the SCR1 gate to work. Or drive the motor, turning it. Motor speed can be achieved by adjusting VR1.
The input pin of the IC1 power supply 14 is filtered to smooth the current through D2 and C2. The D1 prevents engine noise. And D3 is the reverse voltage protection of the motors. This may cause damage to the circuit. If the circuit is used with a motor that consumes more energy. The heat sink must be connected to BD1, D1 and SCR1, because they heat up. It may cause damage to the equipment.
![[Image: dc-motor-controller-with-scr-ic-cmos.jpg]](http://www.eleccircuit.com/wp-content/uploads/2011/06/dc-motor-controller-with-scr-ic-cmos.jpg)
This is DC 12V motor speed motor controller circuit. As the SCR DC motor speed control circuit using IC-CMOS. You can adjust the rotation speed of the spindle motor from 5-60 cycles per minute. The work of the circuit, the IC1- (CD4081) is gate door type ic. Accepts the bridge diode voltage BD1. But there is no filter to regulate the current. The other on pin 2. The VR1, C1 and R1 is a phase change or delay time, the voltage from pin 3 to the triggers pin the SCR1 gate to work. Or drive the motor, turning it. Motor speed can be achieved by adjusting VR1.
The input pin of the IC1 power supply 14 is filtered to smooth the current through D2 and C2. The D1 prevents engine noise. And D3 is the reverse voltage protection of the motors. This may cause damage to the circuit. If the circuit is used with a motor that consumes more energy. The heat sink must be connected to BD1, D1 and SCR1, because they heat up. It may cause damage to the equipment.
