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Simple high and low voltage circuit breaker with delays and

2015-01-12 18:53  
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This article explains the simple high and low voltage circuit breaker with delayed and music. The circuit is simple but effective. For your more thorough grasp of this principle, we suggest that you can know more about some of the important components of the circuit, such as: 1N4001 . This simple circuit will protect expensive equipment from the high and low voltage and voltage surges (when power is restored). It also gives a melodious tune when mains power resumes. When the supply voltage is normal, the DC voltage at the cathode of zener diode D4 is less than 5.6 v. Therefore, the transistor T1 is turned off. The cathode of the DC voltage is greater than 5.6 v zener diode D5 and results in the transistor T2 'state. Therefore, the relay RL1 become energetic, which is displayed green LED lights up. In the high supply voltage conditions, the transistor T1 switches "state, because the voltage at the cathode of zener diode D4 becomes greater than 5.6 v. Accordingly, transistor T2 switches to the OFF state, the relay is disconnected, at low supply voltage condition, transistor T1 switch to the off state and the result transistor T2 is switched to the oFF state, the relay to disconnect the timer circuit IC 555 is configured to run in a monostable mode. pulse width of about 10 seconds timing component values ??for the circuit. when power is restored after the break, pin 2 of the IC 555 lower, which triggers it short. whose output makes music IC UM66 operating through transistor T3. simultaneously, has also been used as a forward bias transistor T1 monostable IC1 output is connected to it bottom of the diode D8 and resistor R7. Accordingly, for the transistors T1 and T2 transistors biased off, so the relay RL1 time still being suppressed, and the load of the mono pulse voltage surge protection.
Adjust preset VR1 and VR2, you might use a manual variable autotransformer. Set the output autotransformer to 270 v AC and connect it to the main transformer X1. Adjust preset VR1 such relay RL1 just de-energises. Next set of output autotransformer 170 v AC. Now adjust preset VR2 so that relay RL1 de-energises again. Volume control VR3 may be adjusted as desired to adjust the output volume generated by the IC UM66. 

Self switching Power Supply


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