555 timer based projects list

Keypad Encoder IC with Serial Output Schematic Circuit Diagram The EDE1144 Keypad Encoder IC from E•Lab Digital Engineering (www.elabinc.com) is designed to interface a matrix-type 4 row × 4 column (16-key or less) keypad to a microcontroller or other…

SW Converter for Digital AM Car Radio Schematic Circuit Diagram This circuit is purposely presented with many loose ends (not literally, of course) to stimulate experimenting with RF circuitry at a small outlay. Looking at the circuit diagram you may…

Alternating Blinker Schematic Circuit Diagram The circuit represents a general-purpose astable multivibrator that alternatively energizes two heavy loads via a relay (in this case, the loads are 12-V incandescent lamps). In contrast to an ‘analogue’…

Simple Remote Control Tester Schematic Circuit Diagram Nearly always when a remote control doesn’t work, the underlying problem is elementary: the unit does not emit light. The cause may be dry solder joints, defective LEDs etc., but…

The LM3410 LED Driver Schematic Circuit Diagram The LM3410 IC is a constant current LED driver useful in either boost converter or SEPIC design applications. A SEPIC (Single Ended Primary Inductance Converter) design allows the power supply’s…

Automatic Rear Bicycle Light Schematic Circuit Diagram This is a design for a rear bicycle light that automatically switches on and off according to ambient lighting conditions. The red LEDs flash with a 50 % duty cycle…

Variable Crystal Filter Schematic Circuit Diagram Crystal filters are often used for IF filters in receivers, where the bandwidth of this filter largely determines the selectivity of the receiver. The unique feature of the filter described…

Voltage Difference Magnifier Schematic Circuit Diagram This circuit was designed for monitoring the charge- and discharge process of a 6-V lead-acid battery. This process takes place between 6.2 V and 6.8 V. The author used a…

Wireless Alarm Transmitter and Receiver Schematic Circuit Diagram Here are two circuits that make it possible to add up to eight detectors to an existing alarm system without running a single cable. Each transmitter has a unique number…

LED Tester Schematic Circuit Diagram In some circumstances, it may be necessary to select LEDs with closely matched characteristics. This design makes the job a whole lot easier. It uses two tracking current sources to…

Electret Mic Booster Schematic Circuit Diagram Anyone who’s spent much time searching the web for interesting circuits is likely to have found at least one TL431 based audio amplifier, the circuit is based on the principle…

Green/Red Multiflasher Schematic Circuit Diagram This circuit can be made to produce interesting and attractive light effects using just a cluster of red LEDs and one of the green LEDs. One effect is first alternating between…

Bench PSU for PC Schematic Circuit Diagram Given that every PC has a powerful, well-regulated PSU that supplies, among other things, a 12 V rail, why not make use of it to produce a PSU variable from…

Virtual 9 V Battery Schematic Circuit Diagram PP3-size 9 V batteries (IEC: 6LR22) have a considerably poorer price/energy ratio than 1.5 V AA (IEC: LR6) cells. This makes it all the more unfortunate when you accidentally leave…