Hello everyone,

I have some doubts concerning the use of BJT as a switch. I have a voltage square signal input that swings between 3V and 0V. At the output I have to be able to distinguish a logic '1' between 0V and -0,5V; and a logic '0' beyond -3V. So that I need to supply the transistor with GND as the most positive voltage and a negative voltage as the most negative supply voltage (I am free to choose this negative value, could be any value). I wonder if this is possible and if anybody could lend a hand with a basics tips to design it would be helpful.

Thanks in advance.

 

hi mee,
Welcome to AAC.
As this is a College assignment, please post your attempt at solving the assignment, so that we can guide you through the problem.
It is AAC's policy not to provide a final answer.

E

 

A tip is to consider both NPN and PNP transistors.