Relay Voltage Issue SOLVED

Hi, I'm building a circuit that uses a relay and op-amp to simulate the staggered charging of two capacitors, C1 (point 2) and C2 (point 4). The goal is for C1 to charge from 0V to approx. 240V, then it discharges into C2 before again drawing power from the 240V supply. The circuit is almost perfect, but I cannot figure out why C1 starts out charged to 240V rather than 0V in the time-based simulation. The rest of the simulation works as it's supposed to, so I was wondering if anyone can give me some insight into why C1 starts off fully charged. Thanks-

by icass22
April 11, 2021

Works fine if you set "skip initial" to yes. I expect that there is a very short startup transient, perhaps built into the software on initial start. Perhaps (again) that's why you have provision skip initial. Don't you think that 10000 seconds run time is a bit masochistic?

by Foxx
April 12, 2021

Just playing with this a bit more. The DC solver puts a charge on C1 and as I remember it the DC solver runs before the time domain.

by Foxx
April 12, 2021

Yes -- you may want to add a Time-Controlled Switch in series with C2 to ensure that it remains uncharged at DC.

by mrobbins
April 12, 2021

1 Answer

Answer by icass22

Great, thanks! The skip initial was the issue.

ACCEPTED +1 vote
by icass22
April 12, 2021

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