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cd4541 timer schematic problem.

 
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another.man_88



Joined: 07 Oct 2006
Posts: 3
Post26 Feb 2007 10:44   cd4541 timer schematic problem.
I have built a cd4541 based timer. timing can be changed by setting a dip switch. while the timer is running, oscillator is monitored using Q1 2n7000 and LED.

After selected time the OUTPUT pin 8 is set high by timer. which in turn switches Q2 another 2n7000. and the output (jumper) should be set high.

while the timer is working file when built on a veroboard, it is not working on the pcb drawn by proteus (ISIS & ARES).

i suspect its due to some kind of schematic error (which resulted in a bad PCB being routed by software).

as this is my first schematic and pcb drawn by a software i would like to know if there is any error in it.

the PCB was autorouted.

as you can see the Q2 source is not grounded and is connected to an OUTPUT Jumper from which i intend to get out for a small DC motor (100-200 ma current draw.) if this is a problem then how should i ground it and still get get output.

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VVV



Joined: 26 Nov 2004
Posts: 1517
Helped: 281
Post26 Feb 2007 18:31   Re: cd4541 timer schematic problem.
I do not see any problem with the schematic, except perhaps the fact that you are running in one-shot mode, but without using the reset input. That means that you can only get one pulse out of the circuit.
Other than that, it should work. If the circuit worked as expected on verctorboard, then there must be some difference. Just re-check the schematic against the old circuit.
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