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Need a simple NOR Gate

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kinarfi

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Need a simple NOR Gate
Will this work or can you suggest something.
Thanks,
Kinarfi
 

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The circuit you provided was a NAND. You need to put the transistors in parallel to produce a NOR.
 
The transistors are also missing the base resistor and the relay coil needs a back-EMF protection diode.


You could also use a single transistor and a diode OR.
 
Hero, if you look at my statement on the drawing, is it a nand or a nor that I need?
1 + 1 = 0
1 + 0 = 0
0 + 1 = 0
0 + 0 = 1
I know I need base resistors and CEMF stuff, diagram is as simple as possible for demo purposes so I left a lot off, but I appreciate the warnings
Kinarfi
 
Why not just put the relay in series with the positive conductor and use a diode OR gate?

How much current can the outputs source and sink?
 
Your truth table is for a NOR gate.

**broken link removed**
 
Is this what you want? Two versions; NOR and OR
 

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Your truth table is for a NOR gate.

**broken link removed**

The diagram in my opening post would work as an AND circuit, being as the coil would energize with only with both inputs at 14 because of the orientation of the transistors.
Mikebits diagram would provide a NOR, but might not power the coil, depending on coil resistance, The diagram here would also act as a NOR by providing power for coil and closing the contact when both input are at 0
or at least, that's how I see it.
Thanks everyone,
Kinarfi
 

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Hi kinarfi,

if space is an issue that single NOR-gate might be the right choice.

Datasheet attached.

Boncuk
 

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Here's how I'd do it.
 

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Because I like FETs so much, and have one that's good for a little over an amp, here's how I plan to do it after looking at all your suggestions.
Thanks for the help, greatly appreciated,
Kinarfi
 

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The application circuit is reversed, unless you forgot to negate the 14V supply. Are you powering up an ignition coil?
 
Not an ignition coil, back when I learned electronics and then mixed it with PLC language, a circle is a common symbol for a relay coil and the contacts are as drawn for N.O. and with a diagonal line thru it for N.C. The circuit is correct and does work as intended. The contact is closed only when both OP-Amps have an out of 0
Kinarfi
 
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