This is a light switch or light activated relay circuit.
Simple an cheap LED flashing cirucit
This circuit only use 2 resistors,1 capacitor, 1 LED and 1 Transistor .
Automatic fan controller
This circuit use LM311,2N3904 and some components
A simple light flashing
This circuit use 2 transistor and some components.
Standalone Linear NiMH/NiCd
This charger requires no microcontroller or firmware
to controller all function only some passive components and one IC.
Electro Meter circuit
This is a simple to measure electrostatic charge circuit.
This is a simple siren circuit.
5.8 watt audio power amplifier
A simple and very cheap audio power amplifier
RS232 transceiver circuit collection
The transceiver circuit that popular for RS232 communication
Basic dual power supply
This is a basic dual power supply that use basic component to generate positive and negative voltage.
Basic regulated power supply
This is an easy regulator that only use zener diode ,transistor ,resisitors and capacitors.