johnsmith123
Member
Hello Guys,
I was wondering how to generate a 1 second negative pulse that would turn on a relay I am using to power up a remote PC. (relay joins two wires for one second, then disconnects)
I have successfully done this with a microcontroller (89C52),a relay and a 2N2907. The relay is only connected for 1 second, then disconnected, using a delay loop within the microcontroller code.
I feel this is overkill and I am looking for an easier way to do this without the microcontroller.
The 1 second pulse does not have to be accurate. The PC is switched on by a momentary push button switch joining two wires. So it can be a 1/2 second pulse or longer, accuracy here is not important. The relay does this as soon as the circuit is powered up, which is hooked to a simple timer.
The circuit I have works perfectly however I am just curious to know how to do it with a few capacitors or resistors if possible.
Anyone have any ideas or sample circuits?
I was wondering how to generate a 1 second negative pulse that would turn on a relay I am using to power up a remote PC. (relay joins two wires for one second, then disconnects)
I have successfully done this with a microcontroller (89C52),a relay and a 2N2907. The relay is only connected for 1 second, then disconnected, using a delay loop within the microcontroller code.
I feel this is overkill and I am looking for an easier way to do this without the microcontroller.
The 1 second pulse does not have to be accurate. The PC is switched on by a momentary push button switch joining two wires. So it can be a 1/2 second pulse or longer, accuracy here is not important. The relay does this as soon as the circuit is powered up, which is hooked to a simple timer.
The circuit I have works perfectly however I am just curious to know how to do it with a few capacitors or resistors if possible.
Anyone have any ideas or sample circuits?
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