2B-UNDER / OVER VOLTAGE CUT OFF
Whenever we operate any TV, VCP, VCR or any other gadget, there is a fear that the gadget may be demaged due to under/ over voltage. Further use of autocut stabilizers can only protect from over voltage. But under voltage is equally dangerous as over voltage. This present project solves this problem. It cuts OFF the circuit under over voltage as well as under voltage condition and saves your gadget.
TECHNICAL DESCRIPTION AND WORKING
This project has been developed and tested O.K. in our TV Engineers Technical Lab. The components and PCB used in the projects published in our books are available for sale at resonable price.
The voltage flactuation in India now-a-days have become a headache for every body. The electronic gadgets can tolerate certain voltage limits. So there is a fear always. Keeping this fact in mind, the present project is developed to save your precious gadgets.
The working of this project mainly depends on two relays. One of these normally remains closed while the other open. When ever the AC voltage is less than 180V, the second relay operates and cuts OFF the circuit. Similarly when the AC voltage is more than 240V, the first relay operates and cuts OFF the circuit. To operate this circuit, only 6V DC is necessary. The preset connected to the circuit can adjust UNDER/OVER voltage cut OFF.
PRECAUTIONS WHILE ASSEMBLING THE PROJECT:-
*While mounting transistor, you should connect collector , base & emitter properly.
*Please use resistance of the exact value as given in the circuit.
*Check polarity of diodes [anode and cathode]
*First of all check all the components as per circuit.
BC 148 = 2
RELAY 6V = 2
ZEENER 6V = 2
4.7K = 2
10K = 2