Search found 47 matches

by 1moldmaker
Fri Sep 20, 2019 1:52 pm
Forum: General Discussion
Topic: Voltage spike
Replies: 9
Views: 324

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: 324

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: 324

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: 324

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: 324

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: 2332

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: 2332

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: 2332

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: 2332

Help with a circuit again

How can I change the polarity of this circuit by using PNP transistors
by 1moldmaker
Wed Apr 17, 2019 4:17 pm
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Re: Having a problem with a triac

Sorry just me being lazy I updated the schematic, I am trying to switch 24 vac, Thanks, I am going to try this when I get a chance
by 1moldmaker
Wed Apr 17, 2019 5:21 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Re: Having a problem with a triac

How would you trigger a triac with a transistor, or would it just stay on and not turn off
by 1moldmaker
Wed Apr 17, 2019 5:09 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Re: Having a problem with a triac

Here is the schematic, I figured it out last night I changed the 150 ohm resistor to 100 ohms works good now, thanks
by 1moldmaker
Tue Apr 16, 2019 7:48 pm
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Re: Having a problem with a triac

any suggestions on how to get around this, should I try a sensitive gate triac?
by 1moldmaker
Tue Apr 16, 2019 8:46 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Re: Having a problem with a triac

at least 10 vac, I do expect a small voltage drop, but not by half
by 1moldmaker
Tue Apr 16, 2019 7:20 am
Forum: General Discussion
Topic: Having a problem with a triac
Replies: 10
Views: 2197

Having a problem with a triac

I am having a problem with a triac BAT16, when I trigger it with an optocoulpler it turns on but the voltage is half of what it should be, Im trying to make a switch for 12 to 24 vac, I have tried a Q4006l triac but still have the same results