Newest circuit diagrams

Under Voltage Circuit

This under voltage circuit may be used as an add-on to an existing power supply or standalone. The circuit draws power from an existing power supply, which may be up to 36 Vdc. Once voltage drops below a preset level the output swings high. A CA3140 MOSFET op-amp is used as a comparator, the output can drive loads of up to 10mA so can drive a low current LED directly. Additional buffering is required for higher loads.

Water-level Indicator

Simple, two-wire, remote monitoring unit Three-LED level display, 9V battery powered

Automatic fading lights

Suitable for 230V incandescent bulbs. Ideal for Christmas decorations

IR Remote Control Extender Mark 5

The latest addition to my collection of Infra Red (IR) Repeater circuits. The Mark 5 is a much improved version of the Mark 1 circuit and has increased range and sensitivity. It is also immune to the effects ofambient light, daylight and other forms of interference. In addition it works with IR modulation freuencies in the range 30 to 120kHz making the Mk5 circuit the best choice for compatibility with remote controls.

Beat Balance Metal Detector

A Beat Balance Metal Detector made from discrete components.

Regulated DC power supply

This is a Regulated DC power supply with short circuit protection and with current limiter.

Cmos 4060 Burglar Alarm

This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of normally-closed input devices - such as magnetic-reed contacts - foil tape - PIRs etc. But it's easy to add a normally-open trigger. When the alarm is activated - the siren will sound for a fixed length of time. Then it will switch off - and remain off. The alarm will not re-activate.

DC Motor Control

Control of the movement of the motor, and an indication of direction provided by LED's.

Camera Switcher

This circuit can be used for multiple cameras with one monitor. The circuit can be operated manually or automatically.

Monitor Splitter

A Simple Splitter Driving Two (or even more) PC Monitors