Search found 53 matches

by 1moldmaker
Sun May 03, 2020 8:17 am
Forum: General Discussion
Topic: Question about a circuit again
Replies: 4
Views: 991

Re: Question about a circuit again

Thanks
by 1moldmaker
Sun May 03, 2020 5:56 am
Forum: General Discussion
Topic: Question about a circuit again
Replies: 4
Views: 991

Re: Question about a circuit again

Thanks the 1.2k voltage divider that I was talking about I was using on a DC circuit
by 1moldmaker
Sat May 02, 2020 4:41 pm
Forum: General Discussion
Topic: Question about a circuit again
Replies: 4
Views: 991

Question about a circuit again

Has any body ever tried to make any of the circuits in the op amp cook book part 4 https://www.nutsvolts.com/magazine/article/op-amp-cookbook-part-4 basically what I am trying to figure out is what resistors and capicatiors would I need to use for only 20 volt AC also would I need a voltage divider ...
by 1moldmaker
Mon Dec 09, 2019 7:11 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2449

Re: Help with a circuit again

I got hold of the the designer and he pointed me in the direction with a revised schematic, this circuit has a a one second delay.
by 1moldmaker
Thu Dec 05, 2019 2:26 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2449

Re: Help with a circuit again

I did
by 1moldmaker
Wed Dec 04, 2019 3:32 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2449

Help with a circuit again

I built this circuit,
http://www.circuitous.ca/AcDcBreaker10.html
It works great, but a its little to sensitive, what I need to know how could I alter it so its delayed, for a second or two, so it would not shut off with the occasional current spike or mini short circuit,

Thanks
by 1moldmaker
Fri Sep 20, 2019 1:52 pm
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 2711

Re: Voltage spike

I was thinking about that, thanks
by 1moldmaker
Fri Sep 20, 2019 8:17 am
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 2711

Re: Voltage spike

To be honest I wouldnt even know where I would put a snubber on my circuit, the problem usually happens when I shut off my transformer at the AC 115v input
by 1moldmaker
Wed Sep 18, 2019 8:54 pm
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 2711

Re: Voltage spike

I was wondering if there was a way to put a decoupling capacitor across where the transformer goes into the circuit. but I dont have a clue on what values of a capacitor and a resistor that I would need to use, the other option that I was thinking of is putting a 1.5KE33ca across where the transform...
by 1moldmaker
Wed Sep 18, 2019 5:42 am
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 2711

Re: Voltage spike

Yes its a homebrew emitter follower ac voltage regulator, the circuit on the right is for short circuits the darlington transistors get quite hot sometimes with a load, I use a 24 vac 6 amp transformer through this circuit
by 1moldmaker
Tue Sep 17, 2019 12:17 pm
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 2711

Voltage spike

When I shut off my transformer to my power supply I get a voltage spike and every once in a while it will kill one of the power transistors, what can I do to stop this from happening,

Thanks
by 1moldmaker
Fri May 31, 2019 5:14 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2944

Re: Help with a circuit again

Im using the pnp equivalent of a 2n2222a, its a 2n2907a, I am going to bread board this circuit tonight,
thanks again
by 1moldmaker
Wed May 29, 2019 5:07 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2944

Re: Help with a circuit again

thanks, never even thought of switching the leads going into the optocoupler
by 1moldmaker
Wed May 29, 2019 5:27 am
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2944

Re: Help with a circuit again

This is a circuit for Lionel trains that run on 0-18 vac. It is not DCC What it does is when it gets a signal of positive dc voltage to the outside rail it turns on the optocoupler and it turns on the whistle, I would like to reverse the polarity so when I send a negative dc voltage to the outside r...
by 1moldmaker
Tue May 28, 2019 5:20 am
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 2944

Help with a circuit again

How can I change the polarity of this circuit by using PNP transistors