thats fine to drive a LED .. but he has an LED and want to use that 'signal' to drive an input on a controller
Rick va3rzs On Fri, Sep 25, 2009 at 11:18 AM, Jim Brown <[email protected]> wrote: > [Attachment(s) <#123f1c9e5df1a41b_TopText> from Jim Brown included > below] > > Here is the circuit I would recommend to light an LED when the signal input > is at or near ground and will extinguish the LED when the input is at or > near + 5 VDC. It would provide minimal loading on a microprocessor output > signal. > > 73 - Jim W5ZIT > > --- On *Fri, 9/25/09, tait700 <[email protected]>* wrote: > > > From: tait700 <[email protected]> > Subject: [Repeater-Builder] Busy Signal (COS) inverter Circuit. > To: [email protected] > Date: Friday, September 25, 2009, 6:33 AM > > > > Hello, > Was wondering if someone knowledgeable would be able to advise me on the > best way to proceed with this, > I need to extract a signal to power a normal LED that indicates when the > Mute has opened on a Receiver. > The Receiver has a "Busy" line coming from the Micro that supplies 5V DC > when the mute is closed ( Quiet ) and goes to OV when the Audio is open ( > Audible ) > I don't have any further info on the current available from the micro and > am a little dubious about running a small SPDT relay off this signal. > I searched the RB site and found the article concerning the "maxtrac cor > buffer" which uses a Transistor to invert the logic but am not sure how to > apply this to a LED ( 20ma ) and whether the resistor on the Base input > would be the right value. > If i could do this without risking the health of the micro ( which controls > everything on the Board ) i would be very happy. > > Any info would be most appreciated, > > Regards, > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > >
