Driving a transistor from HT12D

Thread Starter

André Ferrato

Joined Apr 5, 2015
215
Hello, i intend to drive a transistor from HT12D outputs. I took a quick look through the datasheet and saw the Data Output Source Current and it's negative, this means that i cannot drive an NPN right ? Because i need to feed current to the NPN and as the Output is only sinking... Am i correct ?
 

MikeML

Joined Oct 2, 2009
5,444
Looks like it will source ~1mA. Try 4.7K between the data pin and the base of an NPN whose emitter is tied to Vss (0V).

holt.gif
 

Thread Starter

André Ferrato

Joined Apr 5, 2015
215
Oh i see.. but, when it says SOURCE, it means current getting out of the device right ? So by negative sign it means it's on the opposite direction, so it's SINKING, that's the way i see it or i am missing something ? Some semantics..
 

dl324

Joined Mar 30, 2015
11,230
Oh i see.. but, when it says SOURCE, it means current getting out of the device right ? So by negative sign it means it's on the opposite direction, so it's SINKING, that's the way i see it or i am missing something ? Some semantics..
Source is represented as a negative current, source is represented as a positive current. If you look at the output voltage, it will be apparent which way (conventional) current is going.
 

AnalogKid

Joined Aug 1, 2013
8,534
Oh i see.. but, when it says SOURCE, it means current getting out of the device right ? So by negative sign it means it's on the opposite direction, so it's SINKING, that's the way i see it or i am missing something ? Some semantics..
Semantics - exactly. Your interpretation would be correct except for one thing - the datasheet is not well written in an unambiguous way. DL is correct, the datasheet is confusing, and that's just something you have to live with when 1000 companies are writing datasheets with no absolute rules to follow.

ak
 
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