Search found 42 matches

by 1moldmaker
Fri May 31, 2019 5:14 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 755

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: 755

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: 755

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: 755

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: 1107

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: 1107

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: 1107

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: 1107

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: 1107

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: 1107

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
by 1moldmaker
Thu Oct 25, 2018 10:48 am
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 29
Views: 2105

Re: Need help with a circuit again

Just wondering could this circuit be made with mosfets other than using the 2n3904's, and eliminating the tip127's I have some irf644 mosfets laying around, that way I could I go with a higher voltage with my light bulbs?
by 1moldmaker
Wed Oct 24, 2018 7:18 am
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 29
Views: 2105

Re: Need help with a circuit again

Thanks, do you think I can bread board this schematic using 2n3906 transistors, I would have to wait a week to get the tip127's
by 1moldmaker
Tue Oct 23, 2018 6:32 pm
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 29
Views: 2105

Re: Need help with a circuit again

its like you have to log in twice then you post a reply
by 1moldmaker
Tue Oct 23, 2018 3:39 pm
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 29
Views: 2105

Re: Need help with a circuit again

the light bulbs are14v at 0.22a, I thought the R3 resistor was for the other led.
by 1moldmaker
Tue Oct 23, 2018 1:41 pm
Forum: General Discussion
Topic: Need help with a circuit again
Replies: 29
Views: 2105

Re: Need help with a circuit again

Well I kind of made some changes to the circuit, I took out the 1K resistors and I am using incandescent light bulbs in stead of LED's, also I am running the circuit at 12 to 14 volts, and I am using TIP122 darling transistors instead of 2n3904.