AVR-Chat

At 09:28 PM 30/11/03 -0000, you wrote:
>Hi
>
>I am currently driving an AVR (mega 8) input from a SFH618A 
>optoisolator being driven from the output of a radio control 
>receiver. The input LED is driven from the R/C receiver via a 330R 
>series resistor and the output transistors emmitter is taken to 
>ground with a 3K3 resistor. The transistor collector is taken to +5V 
>and to AVR is driven directly from the transistor emmitter pin. The 
>LED is connected to ground on the R/C receiver. This works fine.

Usually you would ground the emitter and use a pullup resistor
at the collector which feeds the input pin. This would give you
an inverted signal but that would not matter, it would just be
negative active. I would say that 100% of optos would work
this way.


Regards

John Samperi

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