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I am pretty new to electronics and was wondering how you could get a NOT gate for a 9v battery. I understand that it can not make power at the output when there is no power input, so it would probably require multiple inputs. I was basically thinking something like this: Two inputs, A and B One output, C

Input A is always on to give power, and output C Is the opposite of input B.

It seems simple, I just have no idea what this is called, or where you can buy it, do you guys have any ideas?

Edit: Basically I want to connect input A and B from a 9V battery to a device, and I want output C to be the opposite of B, meaning that if I cut the wire between the battery and input B, the output will turn on, getting it's power from input A which is still connected.

Opposite as in on will be off

I do not know much about electronics, so sorry if it is not very specific. Just tell me if you want more clarification.

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    \$\begingroup\$ What is the "opposite"? Can you give an example? Are you talking about inverting amplifier? \$\endgroup\$ – Eugene Sh. Aug 12 '15 at 18:30
  • \$\begingroup\$ I think it would help if you described what you're trying to do with the 9V and why you are looking for a NOT operation on it (a NOT gate only has one input). If you're new to electronics then someone on here can probably provide a much better solution over what you're trying to do with a NOT gate. \$\endgroup\$ – DigitalNinja Aug 12 '15 at 19:27
  • \$\begingroup\$ Sorry, updated it now. \$\endgroup\$ – Sofus Øvretveit Aug 12 '15 at 19:59
  • \$\begingroup\$ Let me see if I understand: you have two devices X and Y. Normally you want X to be powered and Y to be unpowered, but if you cut one of the wires to X then Y will become powered. Is that right? And why cut a wire when you could use a switch? What is your application? \$\endgroup\$ – Justin Aug 13 '15 at 13:18
  • \$\begingroup\$ That is pretty accurate, Justin. I figured I had to use an inverted relay switch, thanks to your help. \$\endgroup\$ – Sofus Øvretveit Aug 13 '15 at 18:18
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A CD4001B with both inputs connected together will act as a NOT gate. Each package contains 4 NOR gates. It will operate from a 9V battery with no other components- the + goes to pin 14 and the - to pin 7.

enter image description here

You could also ground the unused inputs (say pins 5,6, 8, 9 , 12, 13) and leave the unused inputs 4, 10,11 open. The input (1,2) should be near 0V for a '0' and near Vcc for a '1', and the output (pin 3) will be the opposite. It can drive a light load such as a few mA for an indicator LED but not something like a motor.

Such a quad gate in singles should be less than 50 cents. Each gate has about 10 transistors internally, so about 40 altogether.

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A "gate" doesn't usually supply power, but just a small amount of current to drive other gates' inputs. How much current do you need the output to supply? It sounds like you are looking for a relay or P-channel MOSFET instead of a logic gate.

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  • \$\begingroup\$ This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. \$\endgroup\$ – Bence Kaulics Aug 12 '15 at 18:51
  • \$\begingroup\$ @BenceKaulics - My interpretation of the question was that he wants to "make power at the output" when another voltage is low and "[has] no idea what this is called", and my answer is "a P-channel MOSFET instead of a logic gate". My interpretation may be wrong, though. \$\endgroup\$ – Justin Aug 12 '15 at 19:01
  • \$\begingroup\$ You just suggest to use a MOSFET or relay, but do not explain how these parts will act as a NOT gate. And also you ask for more information, so all in all it seemed to me more like a comment. Sorry for that. \$\endgroup\$ – Bence Kaulics Aug 12 '15 at 19:57
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What you want is an XOR logic gate. If your input A will always be powered ON, our input B will be inverted in the output. (There is only one output)

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  • \$\begingroup\$ Welcome to EE.SE! Please note that OP is asking for an analog gate. Also, this question is over three years old. \$\endgroup\$ – winny Sep 24 '18 at 9:15

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