Lcd's cover a wide range of applications including led tv's to cmputer monitors, PDAs, digital monitors and much more. LCD backlight mainly consists of a light source, diaphragm, light leading board and a plastic frame. Cold-cathode fluorescent lamps (CCFLs) have a phosphor coated glass cylinder with cathodes at each end. The CCFL inverter accepts a low-level DC input voltage and provides a high-level AC output to run the backlight CCFL tube. Here's a CCFL tester circuit that often needed to check a faulty LCD backlight circuit for finding the dead components.
Tuesday, March 25, 2014
Sunday, December 15, 2013
Servo Motor Tester Circuit
This circuit allows you to isolate the servo motor from the project circuit and feed it with pulses of varying width nd checking the angle that the servo motor turns to. the circuit is built using two NE555 IC's and a few discrete components. IC1 is set as an astable multivibrator with a time period of 20 ms. Every 20 ms, the astable provides a very sharp negative pulse to trigger IC2. Timer IC2 is configured as a monostable multivibrator that produces 1ms, 1.5ms and 2ms long pulses to rotate the servo motor (M1).
