Newest circuit diagrams

PWM Motor Control

This is a circuit to control motor speed uses pulse width modulation (PWM). The PWM signal is generated by the ubiquitous 555 timer and output current amplified by a power transistor.

Latch Switch

In this circuit a non-locking push switch is used to activate a load. The load remains switched on until power is removed from the circuit.

Shed/Garage Alarm

This is a simple single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays. It's designed to be used with the usual types of normally-closed input devices such as - magnetic-reed contacts - micro switches - foil tape - and PIRs.

Supply Voltage Indicator

A novel supply voltage monitor which uses a LED to show the status of a power supply.

Audio Notch Filter

A variable notch filter with both high and low pass filters.

Energy Leak Detector

High sensitivity, portable temperature comparator Detects draughts around doors, windows, etc.

Hijack Alarm No. 3

This circuit was designed primarily for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when the thief is at a safe distance - the Siren will sound.

E-B-C Transistor Pin Identifier

Tests transistors and diodes for polarity. Simple circuitry - 9V Battery operation

Regulated 12 Volt Supply

A basic regulated 12 Volt power supply

Bells ring Generator

Three circuit options. Can be synchronized to Christmas tree flashing lights