Led controlled (On/Off) by a PIC

lb_so · Joined: 01 Jan 2013 Posts: 1

I have a LED whose Anode is connected to a 5V source. I need to switch it On/Off. For the On position, I used output_low command.
What command do I need to switch it Off. Output_high or input_low(high)?
For output_high I'm thinking not to damage my PIC, having 2 sources of 5V.
I'm using a PIC 16F876. Thank you!

ezflyr · Joined: 25 Oct 2010 Posts: 1019 Location: Tewksbury, MA

Hi,

You'll need a current limiting resistor in series with the LED. A 300 ohm
resistor would be a good choice.

To turn On the LED you would use output_low(LED), and to turn Off the LED
you would use output_high(LED).

John

unisaco · Joined: 03 Dec 2012 Posts: 6

That's popular method when design hardware. It's mean we just control directly turn on LED by 0 level logic (due to low current at I/O port).
You need to use 1 resistor (value: 330 ohm) in series to any pins of LED.
Base on this design:
output_low: LED on
output_high: LED off