Transistor as a switch for signal.

Thread Starter

Manar Zaaboub

Joined Aug 18, 2016
1
Hi,
lately I was hired to sit in a room with all of the electronic kit that I need to build whatever project I ever had in mind. For this reason I considered joining an online community for electronics, and I have chosen this forum because I already have been a member here a couple of years back, and I am glad that I am back again.
The question is as this simple. How can a transistor be used as a switch, that is when closed can let a signal go through and when opened the signal is blocked ?. The signal is carrying information so when the switch is closed, the output (emitter) has to be exactly the same as the original signal, so that it can be parsed afterwards .

I appreciate your help.
Manar Zz
 

MaxHeadRoom

Joined Jul 18, 2013
28,617
Do you want a switch or a linear analogue/amplifier?
If the signal is digital, then the switch mode can be used.
For a simple switch see 2n5551 BJT etc.
Max.
 

crutschow

Joined Mar 14, 2008
34,281
For the most accurate analog switching you should use a MOSFET, which look like a low resistance when ON.
A BJT has a small offset when ON that can slightly distort the signal.

If you tells us the parameters of the signal you want to switch, we can give you a better answer.
 

hp1729

Joined Nov 23, 2015
2,304
Design 812 a.PNG
Hi,
lately I was hired to sit in a room with all of the electronic kit that I need to build whatever project I ever had in mind. For this reason I considered joining an online community for electronics, and I have chosen this forum because I already have been a member here a couple of years back, and I am glad that I am back again.
The question is as this simple. How can a transistor be used as a switch, that is when closed can let a signal go through and when opened the signal is blocked ?. The signal is carrying information so when the switch is closed, the output (emitter) has to be exactly the same as the original signal, so that it can be parsed afterwards .

I appreciate your help.
Manar Zz
As crutschow suggested (simplified maybe).
 
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