Why BJT is used here?

Thread Starter

skybox

Joined Mar 2, 2009
68
Hi guys,

Was look at a schematic earlier was confused on why the BJT was used in the following situation? The REC_OK is a signal sent from the DB-25 connector to the uP, which tells the uP that the DVR is recording fine.
 

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Bychon

Joined Mar 12, 2010
469
The bjt amplifies and inverts the signal. The inversion might be important, and the amplification might not be important.
 

Thread Starter

skybox

Joined Mar 2, 2009
68
Thank you. Just read more about the common emitter amplifier. The spec sheet on the DVR doesn't give much information on it.
 

kingdano

Joined Apr 14, 2010
377
simple inverter - likely translates to the proper logic level as well - as was already suggested.
 
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