Random circuits

Here are some of over 800 projects from our free circuit diagrams database. For more, try browsing categories menu on the left.

Transistor / Diode / IC (DIP) Outlines

Transistor / Diode / IC (DIP) Outlines... [read more]

Dome Lamp Dimmer

There are times when a little light inside the car would greatly assist one of the passengers but the dome light is too bright for safe driving.... [read more]

Car Battery 6V or 12V charger

This circuit can charge automatically, fast and rightly, batteries 6V and 12V. A basic factor in the success in the circuit operation is the use of transformer [T1] of good quality with very good insulation and resistance in the short circuits.... [read more]

Solar Cell Voltage Regulator

This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The circuit consists only of one 5V regulator, two transistors, two LEDs, five resistors, two capacitors, and one small battery. Although a 4-V battery is indicated, 4.5 V (3 alkalines in series) or 3.6 V (3 NiCd cells in series) will also work.... [read more]

Two-Led Pilot Light

This circuit is designed on request and can be useful to those whishing to have, say, a red LED illuminated when an appliance is on and a green LED illuminated when the same appliance is off. Any mains operated appliance can be monitored by this circuit provided a suitable mains switch, capable of withstanding the full load current, is used for SW1.When SW1 is closed, the load and D4 are energized, Q1 is saturated and shorts D3, thus preventing its illumination.... [read more]

Infa-Red Remote Control

his remote transmits a tone using an infa-red LED. This tone is decoded by the receiver. Since the receiver only switches when it "hears" the tone, there are no accidental activations.... [read more]