12v timers
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Power Off Delay Relay circuits
The two circuits below illustrate opening a relay contact a short time after the ignition or light switch is turned off. The capacitor is charged and the relay is closed when the voltage at the diode anode rises to +12...
APPLIANCE TIMER
This circuit controls intervals of up to 1 hour in 1-second increments, as programmed by thumb wheel switches S1 and S2. It consists of a two-stage programmed counter driven by a 1-second clock derived from the 60-Hz power line. The...
Amp It Up!
This tutorial demonstrates how to create a small relay interface board that allows U4x1 devices to control circuits requiring higher current or voltage than the U4x1 devices can provide directly. It is designed for users of U4x1 devices with custom...
Relay Coil Energy Saver
Some relays may become warm if they remain energized for an extended period. The circuit presented here will actuate the relay as before but will reduce the hold current through the relay coil by approximately 50%, significantly decreasing heat dissipation...
Jogging Timer
This circuit was developed in response to requests from visitors for a timer that can emit a beep after intervals of one, two, three minutes, and so forth, suitable for jogging purposes. As illustrated in the circuit diagram, SW1 is...
5 Minute Signal
For the past year and a half, a group based in Ann Arbor, Michigan, named GO-Tech has been formed, uniting individuals interested in creating projects using technology, such as hardware, software, metal, and wood. This initiative is referred to as...
Jogging Timer
This circuit was developed since a number of visitors of this website requested a timer capable of emitting a beep after one, two, three minutes and so on, for jogging purposes. As shown in the Circuit diagram, SW1 is a...
Appliance Cutoff Timer
Suitable for cutting off an appliance or other AC load, this timer will cut the AC power after a period determined by R1/C3, as shown, for about 40 minutes. K1 is a relay that should handle about 10 A. S1A...
Switch Timer For Bathroom Light
This 9-minute timer switch is designed to control lighting in a toilet or bathroom. The timer is activated by pressing switch S1 and deactivated by pressing S1 again. If the switch is not turned off, the light will automatically turn...