twchapman63
New Member
I am building this led voltage meter using the lm339 IC (link at bottom) and have run into the issue that only the first two leds will light up when measuring voltages 1.5v to 9v. I am curious whether I am using the probes correctly...I use Vin and the ground connected to pin 12 to check the voltage of a giving object and have the ground connected to R5 and +9v connected to a 9v battery pack. I also used a 100k ohm resistor in place of what I believe to be a potentiometer at R1. Any advice would be greatly appreciated.
Here is the link:
http://www.ecelab.com/circuit-simple-led-voltmeter.htm
Here is the link:
http://www.ecelab.com/circuit-simple-led-voltmeter.htm