0 Simple Remote Control Checker

This is a simple infrared (IR) remote checker.  The two versions are shown below, the one using NPN transistor and other using PNP transistor. Both of the remote checkers can be used to test remote control of TV, DVD players, and other devices or equipment.

Part List:

R - 47 kilo-ohms 1/4W

LED - 3mm or 5mm red LED (yellow, orange can be used also)

LDR - any light dependent resistor that varies from 300   to 10Meg

Q1 - 2N3906, 2N4403, CS9012 , or any similar PNP transistor

Q2 - 2N2222, 2N3904, CS 9013, or any similar NPN transistor

 Parts diagram click to enlarge:

PNP pins

NPN pins

LDR

Note: Increasing the value of R increases the circuit sensitivity. Meaning if the LED is always on even no light is directed to the LDR, try decreasing the value of R. On the other hand, if the LED will not light up even a light is directed to the LDR, try increasing the value of R.