Hi there,
I have a circuit here that looks like this: **broken link removed**
my problem is, how could i apply a power on reset for this circuit because everytime I apply power on it the relay energizes. I have already used the other flipflop on the 4013 for other purposes. Thanks in advance!
I would move one end of 1N4148 to +12V instead of Q output and exchange physically the 1M resistor and capacitor.
So the capacitor ends up being connected between +12V and pin10, with a diode to discharge it should +12V is off. The 1M resistor from pin10 to 0V charges up the capacitor during power ON and releasing the reset on the latch a few moment later.
I would move one end of 1N4148 to +12V instead of Q output and exchange physically the 1M resistor and capacitor.
So the capacitor ends up being connected between +12V and pin10, with a diode to discharge it should +12V is off. The 1M resistor from pin10 to 0V charges up the capacitor during power ON and releasing the reset on the latch a few moment later.
He's making a one-shot, i.e., a monostable multivibrator. Each time he triggers it on "+pulse in", he wants a short pulse at the Q2 output. The circuit he has drawn will do that. I don't think your idea will.
i did the modifications Ron mentioned but i think the flipflop is in reset state all the time...
Any more inputs? this is the only part of my circuit that is not working as expected... Thanks in advance.
It could be the one-shot delay is too short for you to notice.
Before trying Kchriste's suggestion, which is a proper one by the way, you may try to increase the 1M resistor to 10M and/or increase the value of capacitor to 10uF as the previous values give a very short timing period.
i did the modifications Ron mentioned but i think the flipflop is in reset state all the time...
Any more inputs? this is the only part of my circuit that is not working as expected... Thanks in advance.
nok6600app:
the circuit schematic does not show the connection
to the circuit that is to generate the trigger signal on pin_11, CP2.
The 4013 is a CMOS device very high Input impedance.
If it is Left Open Circuit for tsting, pin_11 might couple turn-on transients to the CMOS that trigger the 4013.
Rule: Always connect unused digital circuit inputs to Gnd when not used. For testing use these inputs can be held down thru a 100k resistor.