What's the opposite of a NOT gate?

  • Thread starter Thread starter golmschenk
  • Start date Start date
  • Tags Tags
    Gate
AI Thread Summary
The discussion centers on finding a circuit component that acts as the opposite of a NOT gate, specifically a buffer that allows a lower current signal to control a higher current output without altering the signal itself. Various solutions are proposed, including using two NOT gates in series, an AND gate with identical inputs, or dedicated buffer chips. An op-amp voltage follower is also suggested as a potential alternative. The conversation highlights that buffers do not modify the logic of the signal but are essential for driving higher loads. Ultimately, the focus is on ensuring the sensitive circuitry can operate without needing to handle higher current levels directly.
golmschenk
Messages
35
Reaction score
0
I essentially need the opposite of a NOT gate. I know that sounds silly, but what I'm really looking for is something that will provide the current based on the signal sent to it so that the more sensitive circuitry sending the signal doesn't have to run higher current levels. I've found I could do this using two NOT gates in a row or an AND gate and just using both the inputs on the AND gate to be the same, but I'm guessing there must be a circuit piece already built for this. One that I can provide a signal and supply voltage to and it will provide the output current. For what I'm doing the signal voltage and supply voltage need not be the same. I just need to make sure the circuitry sending the signal doesn't have to send the higher current with the signal itself. Thanks!
 
Engineering news on Phys.org
What you are describing is called a http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/buffer.html" .
 
Last edited by a moderator:
Are you looking for a relay?

Edit: Jambaugh looks more capable at this, I'd look at his suggestion first :)[/size]
 
OK, so you want a buffer.

Using two NOT gates, or an AND gate, or some other form of buffer made from whatever logic gate chips you have available should be fine.

Alternatively, maybe use an opamp voltage follower? Or investigate buying dedicated buffer chips.
 
A buffer is made of 2 inverters internally. If you need to drive a long distance and need 2 (or any even number) buffers, using a series of even number of inverters is a better solution.

If you don't care about the difference in rise time and fall time, you can use pretty much any combinational logic gate to make it a buffer.
 
Last edited:
Awesome. Thanks for the help!
 
So the natural progression is "AND, OR, NAND, NOR, NOT, BUFFER"? Sorry, but that just doesn't sound right to me (linguistically). Let me do some research.
 
Also called a follower.
 
mhearne said:
So the natural progression is "AND, OR, NAND, NOR, NOT, BUFFER"? Sorry, but that just doesn't sound right to me (linguistically). Let me do some research.
What "progression"?

Buffers aren't really considered a logic function, since they don't really do anything to the signal, logically speaking. They just help it drive higher loads.
 
Back
Top