PWM Dimming for LED RGB Video Displays

This is an application that can be used to adjust LED brightness while maintaining superior color quality. This application uses pulse width modulation (PWM) dimming technique. This application can be used for single-line scrolling displays, transportation road signs, simple scoreboards, ever-expanding advertising markets encompassing convenience gas stations, shops, stadiums, and stores. Following figures shows color shift caused by analog dimming, […]

Read more

AC Powered-LED Flasher

Based on a request by FreeCircuitDiagram reader Helynn Schufletowski, here we present an AC powered-LED flasher circuit for all of you! DEADLY ELECTRICAL SHOCK WARNING: This circuit is not isolated from mains supply, don’t touch it when it’s plugged to the power line. The circuit is based on our previous transistor LED flasher circuit, but we added a transformer-less ac […]

Read more

1.5V LED FLasher Using 3 Transistors

LED flasher circuit here will flash a LED using only 1.5 volts  supply voltage. Normally, to make any LED lamp works, you need more than 2 volts power supply. This because LED will work only when the supply voltage is higher than its forward bias voltage, around 2 volts  for red LED, and slightly lower for other color (but still […]

Read more

LED Flasher Using 555 IC

This LED flasher give similar circuit with the previous transistor LED flasher, but this circuit use a 555  integrated circuit chip as the active component. Here is the schematic diagram of the LED flasher circuit: This circuit gives alternating LED flashing, but with different flashing period between LED 1 and LED 2. The ON period of the LED 1 is […]

Read more

LED Flasher Circuit Using Transistors

Classic LED Flasher Circuit This LED flasher circuit is a classic two transistor flip flop. This flasher circuit is very popular and it’s usually the first circuit to build when starting electronic circuit building hobby. Here is the schematic diagram of the famous LED flasher circuit: How LED Flasher Circuit Works The circuit consist of two transistors, two capacitors, four […]

Read more

AC Powered-LED Circuit

The high durability nature of a light emitting diode (LED) make it suitable for ON/OFF indicator application. Because the limitation on low operating voltage, LEDs are normally applied on low voltage application.  Fortunately, there is a simple method to apply LED indicator for high powerline voltage: reactance of a capacitor can be used to limit the current without dissipating any […]

Read more
1 2 3 4