Help Me Adapt This Circuit

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Mario
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Help Me Adapt This Circuit

Post by Mario » Tue Jun 23, 2009 4:46 pm

I'm making a remote to control different lights in my room and want it so when I push the button once it turns the light off, press it again and it turns on. So I needed a flip-flop circuit, and I remembered this one by Daftmike:

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I've built the circuit before, and it works fine. But I only had one MOSFET. I only need to switch a small amount of power for a relay, so I tried replacing the MOSFET with a transistor, but it didn't work.

So here's my question: Is it possible to replace the MOSFET with a common transistor, or do I need to buy more MOSFETS?
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timmeh87
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Re: Help Me Adapt This Circuit

Post by timmeh87 » Tue Jun 23, 2009 7:21 pm

Yeah It should work fine if its connected properly.

But cant you just buy latching switches.... Like the ones on guitar pedals...
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Mario
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Re: Help Me Adapt This Circuit

Post by Mario » Tue Jun 23, 2009 7:37 pm

I'm trying to buy as little as possible; If I can get the transistor to work instead of the MOSFET, I won't have to buy a single thing for the whole project.

How should I connect the transistor? B to G, C to D and E to S?
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timmeh87
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Re: Help Me Adapt This Circuit

Post by timmeh87 » Tue Jun 23, 2009 8:27 pm

Not exactly... TBH i have no idea what that thing up there is. Ive never had to deal with a flip flop outside of an IC
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codeman
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Re: Help Me Adapt This Circuit

Post by codeman » Wed Jun 24, 2009 10:38 pm

Replacing it with an NPN transistor should work....if you change the resistor values. R1 and R3 are huge, so there's probably just not enough base current drive to turn the transistor on. A MOSFET doesn't have to worry about that since the input gate is basically just a capacitor and no DC current needs to flow like is necessary for an NPN. If you change R1 and R3, you'll probably have to change the capacitance value also, but it should work.
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Mario
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Re: Help Me Adapt This Circuit

Post by Mario » Thu Jun 25, 2009 10:38 am

Any idea what they should be changed to? Thanks. :)
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