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Circult Help - isolate circuits Help

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Huttojb1

Member
Hey all.

I have built a circuit which was orginal supported by you guys on here.

Here is the original link - http://www.electro-tech-online.com/threads/transistor-damage-needs-protection.149898/

But now i have connected all the circuits together and now I'm not getting the correct results as I expected.

I need to explain the circuit alittle so everyone can understand.



Ok Circuit B is the master switch on. This is switched on for a period of time (Activating NPN3). Whilst NPN3 is active Circuit A - 1 and Curcuit A - 2 is switched on from the PIC (Switching on NPN1 and NPN4) Now I can switch off NPN3 and both RL1 and RL2 are still energised.

Now comes to my issue, When switching off NPN1, RL1 should switch off and leave RL2 on, but it isn't. When switching off NPN4, RL2 should switch off, and leave on RL1 (or vice-a-versa)

There are going to be a few more Curcuit A - x (Probably about another 4). Can some one help me to isolate each circuit - it seems that the curcuits are effecting each other. When Each one is connected inderpendantly it works....

Hope this makes sense.....!!

Jason
 

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Huttojb1

Member
Would putting some IN4148 inline be ok - see attached?

upload_2017-6-13_21-18-48.png
 

Diver300

Well-Known Member
Most Helpful Member
Have you got this sorted?

I can't see the reason for R4, R5, D2 & NPN2 or the equivalents on the other circuit. All you need is a diode like you added in your second post.

I assume that circuit B is to turn on the all the relays? I was going to suggest a base - emitter resistor to ensure that is turned off when not needed but you've added that.
 

Huttojb1

Member
Have you got this sorted?
Depends what you mean sorted, have I built it, and it's operating as it should - yes, I have implemented the cct and it seems to work.

Do I know if it's gonna cause any damage in certain conditions, unfortunately No. this is why I put it on here for anyone's input. I was asking that if I use the IN4148 in this cct would they be ok, with the lack of response I presume they are ok, otherwise I would have everyone jumping up and down on me!! Lol.

I can't see the reason for R4, R5, D2 & NPN2 or the equivalents on the other circuit. All you need is a diode like you added in your second post.
If you look at post #1. There is a original link, MikeM and Spec helped me with the fundamental of the cct and currently it's working good.

I assume that circuit B is to turn on the all the relays? I was going to suggest a base - emitter resistor to ensure that is turned off when not needed but you've added that.
The concept of the cct is NPN1 or NPN3 can activate the relay. Again this is explain in original post.

Jason.
 
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