# Help designing a circuit

#### nachobalasch

Mar 28, 2022
3
Hello,

I'm trying to design a circuit for a class project that does the following:

//Textual explanation
Two Inputs: a and b. One Output: c
a
is a continuous signal that I'm trying to measure (in c) but only if b has been turned on as well. If a stops, then you again need b in order to get c.

//Graphic explanation
I've attached a file.

If you know any way that I can design a circuit to work like this passively, I would love to hear it. Thank you very much for taking the time to read this.

#### Attachments

• Circuit.pdf
65.9 KB · Views: 12

#### AnalogKid

Jun 10, 2015
2,702
1. What do you mean by "variable signal"?

2. Which signals are digital and which signals are analog?

3. the leftmost image has an unlabeled input.

4. Is the output signal analog, digital, exactly equal to the "variable signal", or something else?

ak

#### nachobalasch

Mar 28, 2022
3
1. What do you mean by "variable signal"?

2. Which signals are digital and which signals are analog?

3. the leftmost image has an unlabeled input.

4. Is the output signal analog, digital, exactly equal to the "variable signal", or something else?

ak
Hello, thank you for your reply! I’ll try to clarify my question as best as I can.
1. Variable signal: a voltage produced by a thermoelectric generator -> probably a ~continuous current.
2. The second input would be a digital input. The output would be analogue. It needs to work without a power source.
3. The second input is a digital input that, alongside the initial input, makes the machine produce an output or in other words, let’s the input pass through.
4. It doesn’t really matter what the output is as long as it is measurable.

#### AnalogKid

Jun 10, 2015
2,702
It sounds like what you want is an analog switch or transmission gate. These are electronic components that require a power source to operate.

Another option is low-power relay.

ak

Moderator
Nov 17, 2011
13,102

Moderator
Nov 17, 2011
13,102
Look up relays.

Mar 28, 2022
3

#### Keonte45

Aug 29, 2022
82
Hello, thank you for your reply! I’ll try to clarify my question as best as I can.
1. Variable signal: a voltage produced by a thermoelectric generator -> probably a ~continuous current.
2. The second input would be a digital input. The output would be analogue. It needs to work without a power source.
3. The second input is a digital input that, alongside the initial input, makes the machine produce an output or in other words, let’s the input pass through.
4. It doesn’t really matter what the output is as long as it is measurable.
Thank you

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