GatorGnet New Member Feb 19, 2010 #1 I know that each pin can't handle a lot but would I be able to get away with driving a 5mm red LED and a transistor from one pic pin?
I know that each pin can't handle a lot but would I be able to get away with driving a 5mm red LED and a transistor from one pic pin?
ericgibbs Well-Known Member Most Helpful Member Feb 19, 2010 #2 GatorGnet said: I know that each pin can't handle a lot but would I be able to get away with driving a 5mm red LED and a transistor from one pic pin? Click to expand... hi Gator, The PIC is rated to source up to approx 20mA on a output pin. If you assumed that the RED led had a Vdrop of 2v, then thats 3V/0.01= 300R for 10mA thru the led. This leaves about 10mA for the transistor base resistor. OK.?
GatorGnet said: I know that each pin can't handle a lot but would I be able to get away with driving a 5mm red LED and a transistor from one pic pin? Click to expand... hi Gator, The PIC is rated to source up to approx 20mA on a output pin. If you assumed that the RED led had a Vdrop of 2v, then thats 3V/0.01= 300R for 10mA thru the led. This leaves about 10mA for the transistor base resistor. OK.?
geko Active Member Feb 19, 2010 #3 Connect the LED + resistor in series with the base of the transistor, then the LED current also drives the transistor. Something like the schematic in this document show. **broken link removed**
Connect the LED + resistor in series with the base of the transistor, then the LED current also drives the transistor. Something like the schematic in this document show. **broken link removed**