Analog muxing with only 1 power source.

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lddang

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Hi I am a recent graduate and still have a long way in learning analog design and I need help with one of my problem. I want to design some sort of 'selecting/switching mechanism' that chooses between 2 inputs (Vs and GND) to output all depending on what a third signal (Select) is, essentially a 2:1 mux (refer to picture).
And the following truth table as follows.
SelectVout
0Vs
1GND

Here's the kicker. Vs is the only power source in the circuit. I have no idea or where to begin on how to power the "switching/selecting" mechanism if I cannot use another power source to do so. Bascially "SELECT" is a jumper that either close or open to do the selection.
 

Vs is an input the MUX and so another input is required in the select line to toggle between the two inputs you are going to select between
 

Here is a really simplified idea of what I am trying to get at. .
If J1=1, Vo=GND,
if J1=0,Vo=Vs.

Of course this is not what I want because while J1 is '1' current will drain to ground. I want to isolate the circuit (not power on at all) when J1 is '1' and when only J1 is open that's when Vo=Vs.
 

lddang said:
... Bascially "SELECT" is a jumper that either close or open to do the selection.
Click to expand...

If you just need an inversion between SELECT and Vout, use an inverter.

If you want to switch different input voltages, use a 4066 type multiplexer (4 such switches in one package).

Both methods get along with a single power supply.
 

Use mosfet they can isolate the circuits easily as in one mode they will be off and in other be on
 

I'm thinking of mosfet. still getting comfortable with them. If using mosfet do I need another suppy voltage? is it possible to use my "Vs" for supply and as an output?
 

I really doubt why you insist on using a single source

It is possible if the Vs is the input and Gate voltage acts as a select line

- - - Updated - - -

Both can be wired using a single Supply
 

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