• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Need a simple NOR Gate

Status
Not open for further replies.

kinarfi

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

Attachments

colin55

Well-Known Member
The circuit you provided was a NAND. You need to put the transistors in parallel to produce a NOR.
 

Hero999

Banned
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.
 

kinarfi

Well-Known Member
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
 

Hero999

Banned
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?
 

Mikebits

Well-Known Member
Your truth table is for a NOR gate.

 

MikeMl

Well-Known Member
Most Helpful Member
Is this what you want? Two versions; NOR and OR
 

Attachments

Last edited:

kinarfi

Well-Known Member
Your truth table is for a NOR gate.

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
 

Attachments

Boncuk

New Member
Hi kinarfi,

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

Datasheet attached.

Boncuk
 

Attachments

Hero999

Banned
Here's how I'd do it.
 

Attachments

kinarfi

Well-Known Member
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
 

Attachments

shokjok

Member
The application circuit is reversed, unless you forgot to negate the 14V supply. Are you powering up an ignition coil?
 

kinarfi

Well-Known Member
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
 
Last edited:
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading

 
Top