Simple (?) Flame Rectification Relay Control

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
I breadboarded the circuit and no joy. Here are the transistors I ended up using:
TR1 = 2N3819, TR2 = NTE129, TR3 = NTE123AP, TR4 = NTE123AP, TR5 = 2N2905A

Do any of those raise a flag as something I need to swap out, and if someone could direct me toward some troubleshooting steps I would greatly appreciate it.
FYI, I do not have the relay hooked into the circuit but am testing for voltage between -12vdc and TR5 collector.

Again, thanks for all the help.
 

Dodgydave

Joined Jun 22, 2012
9,438
Are you using the 15M resistors on the gate, or different values, this can be modified using an op amp window comparator, to give a better voltage swing range.
 

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
Are you using the 15M resistors on the gate, or different values, this can be modified using an op amp window comparator, to give a better voltage swing range.
Yes, I am using two 15M resistors as called out in the schematic. I'm willing to give anything a shot at this point. Can you recommend a particular part number and how to wire it in substitution of the resistors?
 

Dodgydave

Joined Jun 22, 2012
9,438
What i suggest is to add this op amp to the fet source, and adjust the preset pot for maximum voltage swing when the probe is in and out of the flame.Its a inverting op amp, i dont have simulation software , if you need a bigger swing increase the 470K to 1M, so try it and see it may work , if it works you can use the other half of the op amp as a schmitt trigger to drive the relay.



flame.png
 
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Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
What i suggest is to add this op amp to the fet source, and adjust the preset pot for maximum voltage swing when the probe is in and out of the flame.Its a inverting op amp, i dont have simulation software , so try it and see it may work , if it works you can use the other half of the op amp as a schmitt trigger to drive the relay.
View attachment 101846
Next time I run to the parts store I will give this a go. I'm certain at that time I will have more questions. Thanks again for taking the time to respond.
 

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
What i suggest is to add this op amp to the fet source, and adjust the preset pot for maximum voltage swing when the probe is in and out of the flame.Its a inverting op amp, i dont have simulation software , if you need a bigger swing increase the 470K to 1M, so try it and see it may work , if it works you can use the other half of the op amp as a schmitt trigger to drive the relay.
View attachment 101847
Okay, I'm ready to attempt this but need a little clarification of exactly what's staying and what is going. Are you stating I should use the op amp to replace everything not included in your circuit or just replace TR2 and keep everything to the right as it was?

Thanks, and sorry if it should be obvious. I am definitely in over my head with this, but enjoying it nonetheless!
 

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
Still fighting this thing, and changing course a bit.
Now instead of trying to reinvent the circuit, I'm going to try and take something I know works and hopefully tweak it to where I can live with it for now. So back to this circuit:
http://goo.gl/BlOI7x
I think I'm good with all the components needed except I'm fairly clueless as to any kind of spec requirement for the T1 transformer.
Could someone steer me towards what I need to get for this piece?
Thanks.
 

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
I thought you had already bought this product ready made,??
I did. Still have three of them in my desk drawer! But I've already fried the relay on one of them and would like to get the status LED's off the board and onto a panel door. I also would like to beef up the connectors as the ones used are pretty frail. I'm hoping to use the guts of the circuit, as that has tested out pretty well, and get some of the weaker components off board and upgraded.
 

Thread Starter

Jerry Dziuba

Joined Feb 18, 2016
28
So choose a different relay then..
Seemed to me a better option to build from scratch than to try and remove connecters, relay, and LED's from the board and replace them. I could be wrong, I think I've more than proven I'm capable of that in this thread!
 
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