Delay and Music Power Supply Circuit with High and Low Voltage

Delay and Music Power Supply Circuit with High and Low Voltage

Voltage variations and ability cuts abnormally affect assorted equip- ment such as TVs, VCRs, music systems and refrigerators. This simple ambit will assure the cher accessories from aerial as able-bodied as low voltages and the voltage surges (when ability resumes). It additionally gives a accordant tune back mains ability resumes. Back mains voltage is normal, the DC voltage at the cathode of zener diode D4 is beneath afresh 5.6V. As a aftereffect transistor T1 is in off state. The DC voltage at the cathode of zener diode D5 is greater than 5.6V and as a aftereffect transistor T2 is in on state. Consequently, broadcast RL1 gets energised, which is adumbrated by lighting up of blooming LED. Under aerial mains voltage condition, transistor T1 switches to on accompaniment because the voltage at cathode of zener diode D4 becomes greater than 5.6V. Consequently, transistor T2 switches to off state, authoritative the broadcast to de-energise Under low mains voltage condition, transistor T1 switches to off accompaniment and as a aftereffect transistor T2 additionally switches to off state, authoritative the broadcast to de-energise.

Timer IC 555 in the ambit is configured to accomplish in a monostable mode. The beating amplitude is about 10 abnormal with the timing basic ethics acclimated in the circuit. Back the ability resumes afterwards a break, pin 2 of IC 555 goes low briefly and this triggers it. Its achievement makes music IC UM66 to accomplish through transistor T3. Simultaneously, transistor T1 additionally gets advanced biased as the monostable IC1 achievement is affiliated to its abject via diode D8 and resistor R7. As a result, transistor T1 conducts and biases transistor T2 to cut off. Thus broadcast RL1 charcoal de-energised for the continuance of address beating and the amount is adequate adjoin the voltage surges.

To acclimatize presets VR1 and VR2, you may use a manually capricious auto-transformer. Set the achievement of auto-transformer to 270V AC and affix it to the primary of agent X1. Acclimatize preset VR1 such that broadcast RL1 aloof de-energises. Next set the achievement of auto-transformer to 170V AC. Now acclimatize preset VR2 such that broadcast RL1 afresh de-energises. Aggregate ascendancy VR3 may be adapted for the adapted achievement aggregate of the tune generated by IC UM66