Random circuits

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Quiz Circuit

Quiz Circuit... [read more]

220V AC Lamp Toggle Switch Circuit

Due to the low current drawing, the circuit can be supplied from 230Vac mains without a transformer. Supply voltage is reduced to 12Vdc by means of C1 reactance, a two diode rectifier cell D1 & D2 and Zener diode D3. IC1A, IC1B, R2, R3 and C3 form a reliable bounce-free toggle switch operated by P1. R4 and C4, wired to pin #6 of IC1B reset the circuit (lamp off) when power supply is applied. IC1C and IC1D wired in parallel act as a buffer, driving the Gate of the Triac through R5.... [read more]

1.5 Hour Lamp Fader (Sunset Lamp)

The sunset lamp comes on at full brightness and then slowly fades out over 1.5 hours time and stays off until power is recycled.... [read more]

A Hiqh Quality Headphone Amplifier Schematic

Some lovers of High Fidelity headphone listening prefer the use of battery powered headphone amplifiers, not only for portable units but also for home "table" applications. This design is intended to fulfill their needs. An improved output driving capability is gained by making this a push-pull Class-B arrangement. Output power can reach 100mW RMS into a 16 Ohm load at 6V supply with low standing and mean current consumption, allowing long battery duration.... [read more]

Audible Flasher Warning

If you’re a biker or scooter rider you’ll know how easy it is to forget to cancel your flashing indicators after turning without an audible reminder. Constantly glancing at indicator lamps is hardly an option; your eyes should be on the road ahead! The simple circuit shown here provides an audible reminder. The clever bit is the way it doesn’t annoy you by beeping the instant you activate the flashers but only after a preset time, in other words when your indicators are active longer than normal. Supply to the circuit is through the flasher relay.... [read more]

A Cmos Based Motorcycle Alarm

This circuit features an intermittent siren output and automatic reset. It can be operated manually using a key-switch or a hidden switch; but it can also be wired to set itself automatically when you turn-off the ignition. By adding external relays you can immobilize the bike, flash the lights etc. It's easily adapted for a 6-volt system - so it will protect your "Classic Bike"... [read more]