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Fr: retardateur d'alimentation 1 - sortie analogique
With a separate power, allows a system to be powered for a short additional time, from few seconds to few minutes.
I designed it for a fan cooling system.
1) switch on the system
2) switch off the system
3) set the resistor for set the add time
Values in this circuit is E48 serie or more.
This is a scheme of principle with real values... but in practice you need to put protections depending on what you done.
Then go see my circuits "...protection..."
Switch on the power supply charges the capacitor directly, & instantly the voltage is high enough to put the transistor at saturated state.
Switch off the power supply add a resistor in the circuit which slow down the discharge of the capacitor.
Note that the output is reduce by the CMOS voltage conduction.
PS: for an advanced circuit, you should use a binary output (+5V & +0V) rather than my analogic output. Use the transistor for command a relay, or add, after the transistor, a dual trigger comparator as relay.
ESPECIALLY for PWM controled fan, that you may destroy otherwise.
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