Unit 6
Industrial Control Circuits
Presented By :
Ashish Sadavarti

SPEED CONTROL OF FAN USING TRIAC

If R Increases -> Current Decreases-> C charge slowly->
SO DIAC ON Late-> so TRIAC ON Late
(LESS VOLTAGE get to the FAN so fan SPEED DECREASES )
If R Decreases -> Current Increases-> C charge fast->
SO DIAC ON fast-> so TRIAC ON fast
(MORE VOLTAGE get to the FAN so fan SPEED INCREASES )

LIGHT Dimmer CIRCUIT
USING DIAC-TRIAC

If R Increases -> Current Decreases-> C charge slowly->
SO DIAC ON Late-> so TRIAC ON Late
(LESS VOLTAGE get to the LAMP DIM OR LIGHT)
If R Decreases -> Current Increases-> C charge fast->
SO DIAC ON fast-> so TRIAC ON fast
(MORE VOLTAGE get to the LAMP BRIGHT)

BATTERY CHARGER USING SCR

D ON

EMERGENCY LIGHTING SYSTEM

Current (1)->When power supply available then Lamp ON
by full wave Rectifier.
Current (2)-> at the Same time Battery Charge by
second current.

Current ->when power supply not available
then lamp on by Battery through SCR.

TEMPERATURE CONTROLLER
USING SCR

Current-> IN THIS,SCR ON….. SO HEATER ON,
SO TEMPERATURE OF MERCURY In POT INCREASES &
It EXPAND.

No Current-> IN THIS,SCR off….. SO HEATER off,
Because In POT mercury expand so short A & B
terminals(gate cathode terminal of SCR) .

ELECTRONIC TIMER USING SCR

Current -> If switch close, So Capacitor ‘C’ Charge.

• If R2 Increases ->current Decreases-> C charge slowly->
SO UJT ON late-> so SCR ON late
(More Time required for turn on the SCR)
• If R2 Decreases -> current Increases-> C charge fast->
SO UJT ON fast-> so SCR ON fast
(Less Time required for turn on the SCR)

LOW POWER DC FLASHER

Initially Trigger pulse given to SCR1. So SCR1 ON.
Because current (1)-> Lamp ON
Because current (2)-> Capacitor C1 charge of given
polarity.

1) When capacitor C1 full charge then + signal given to
SCR2(anode) & gate signal given to SCR 2. so SCR2 ON.
2) Due to that,negative(reverse) voltage on anode of
SCR1. so SCR 1 off ,SO Lamp also off.
+

UNINTERRUPTED POWER SUPPLY
(UPS)

SWITCH MODE POWER SUPPLY(SMPS)

SWITCH MODE POWER SUPPLY(SMPS)

Thank You