Transistor is not getting biased.

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ism
 
Posts: 5
Joined: Fri Jul 17, 2009 5:47 pm

Transistor is not getting biased.

Post by ism »

Hello,
This Question is regarding the sim reader.
I want to make this circuit work. But I have a problem with the circuit. From the Serial ports 3rd pin a voltage of -12V is coming. If it is so How will the transistor work?
I can understad the reason for the senor Diade placed there but if -12 is coming will the tr get biased? I tried to build this cicuit on a vero board but didnot work out. I found that tr is not biasing. The reason I guess is that the 3rd pin of the RS232 outs -12V.
Please help me to make the circuit work.
Thank you,
ism

adafruit
 
Posts: 12151
Joined: Thu Apr 06, 2006 4:21 pm

Re: Transistor is not getting biased.

Post by adafruit »

oh you're building this on your own? just follow the schematic

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