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4 votes

Timer circuits - difficulty analyzing

Jens has fixed up the 3rd schematic so it should work. As to your question as to why adding the second transistor increases the time, have a look at this simulation- I've used a 400Ω (30mA) relay coil ...
Spehro Pefhany's user avatar
4 votes

Timer circuits - difficulty analyzing

I have fixed the third schematic: Ambivalent wire crossing R4/R5/C1 Polarity of C1 corrected Added GND connection to emitter of Q1 I assume R4 was intended as inrush current limiter for the C1 ...
Jens's user avatar
  • 6,704
1 vote

How can I implement my binary countdown from the output of JK flipflops to two seven segment displays from 15-0?

Your 7seg driver is a BCD to hex. You would have to use a binary to decimal 7 seg driver, or perhaphs much more easy these days, a simple microcontroller. You could just plug your counter bits into ...
DELTA12's user avatar
  • 778
1 vote

Timer circuits - difficulty analyzing

The circuits you show are called single-shot timers, or monostable multivibrators. The latter means that they change state (vibrate - they used to be made with mechanical contacts), but always end up ...
Kuba hasn't forgotten Monica's user avatar
1 vote

A circuit that temporarily keeps the toy on after pressing the button

A simple unipolar solution could be this one: simulate this circuit – Schematic created using CircuitLab C1 is a precharged energy storage and by closing SW1 a part of the charge is ...
Jens's user avatar
  • 6,704

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