Delayed Start

217

01:23:30

Sometimes a circuit needs to be unpowered when the simulation starts, for example due to convergence errors or for an oscillator to start normally. Switches work, but I keep leaving them in the wrong state. I've been wanting a circuit to automatically delay switch-on, but generally don't want to bother when I'm already working on a circuit. They can be a pain to set up. I tried a relay-based one yesterday; it seemed simple but didn't want to work reliably at the simulation speed I needed. I used a FET-based one instead, and had to put up with no current dots in my main circuit. This circuit I think will be free of all these faults. The only thing to really remember is the delay in the logic train.

published 8 years ago

hurz

8 years ago

Yes, as long we didn't had flip flops I used inverter to buildup an simple RS chain and triggered it with an diode High impluse while default after start was managed to be.low. Normaly a simple relais is doing best since they are available.

jason9

8 years ago

What I do is hook up all the grounds into one ground wire and then put a capacitor between the ground and ground wire. That way, no current will want to go into the capacitor leaving the ground wire at zero volts at all times and because of the capacitor the first frame is ungrounded because there is no direct connection to ground and then after that the simulator grounds the circuit through the capacitor. Because the circuit starts at ungrounded all wires at at zero volts including those across the voltage source and then because it grounds after that the voltage source starts being able to deliver power giving an oscillator a kickstart rather than letting fall into equilibrium. Another way to do it is to put an NC push button between the voltage source and the circuit so that you can give it a quick tap to destabilize the equilibrium in oscillators. If a circuit is giving the “Cannot find solution” error then the capacitor trick works best.

eekee

8 years ago

I tried capacitor-coupling the ground in a Colpitts oscilator, it worked just right! Thanks jason9

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.