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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....
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This lovely circuit is a real gem! Easy to assemble and more sensitive than many commercial devices available....
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This circuit is the opposite of Repeating Timer No.3 . Its operation can be limited to the hours of darkness. Again - the variable resistor (preset) lets you choose the level of darkness at which the timer will begin to function....
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This is a combination digital clock timer and solar panel charge controller used to maintain a deep cycle battery from a solar panel. The timer output is used to control a 12 volt load for a 32 minute time interval each day....
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Following a hunch, the author discovered (or re-discovered?) that all plants carry an electric charge relative to the ground. This charge is more or less constant regardless of the size of the plant - a kind of "background voltage" in nature. This electric charge suffuses the entire plant, from its roots to its leaves and fruit. It was measured between a chrome-plated pin inserted into the plant (the positive terminal) and an iron spike driven into the ground (the negative terminal)....
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his circuit proved very useful in keeping away from a terrace or a porch some bats and other nocturnal animals. You can use it for similar or different purposes. The lamp illuminates at a 4-5 seconds delay and stays off about one minute and 15 seconds....
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