Circuits, schematics, electronic projects, electronics kits, tutorials and more

Simple Choc Block Supply

A very simple adjustable power supply can be built on a single piece of chocolate block based on the L200CV IC. The output is variable between 0 and 30V, with an adjustable current limit up to 2 amps.

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Signal Generator

This is a lovely project for home constructors keen on building their own test and measurement (T&M) equipment. It makes use of the ICL8038 signal generator chip, manufactured by Intersil. An improved version, made by Exar corp. is available (XR8038A). It can be used to produce three types of waveforms, sine, square and triangle. The frequency, amplitude and duty cycle can be varied, and selection of waveform is done digitally. To further reduce the complexity, a 3-to-1 switch may be... Read more

70W Class AB Hi-Fi Amplifier

This project considers the development of a 70W Hi-Fi Power Amplifier for use as part of a Hi-Fi separates music system. The design is a fairly simple circuit topology, which is easy to understand and the author believes that the finished result sounds very nice indeed. The web posting is developed from an original design document available in pdf below. The detailed design issues are discussed in the pdf, while this posting discusses the more practical issues involved in producing th... Read more

NiCd Battery Fast Charger

This is an advanced battery charger design based on Maxim's battery charger IC MAX712. This device can, using a minimal set of external components, fast-charge an NiCd/NiMH rechargeable battery. Fast charge is terminated using several detection methods, including dV/dt, dT/dt and a time-based cutout. Full details can be obtained from the MAX712 datasheet, available at the Maxim Inc. Website

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Digitally Controlled Dimmable Lighting

This project implements the control of 2 lighting sets using a PIC18F252 microcontroller. The advantage of the digital controller is its increased flexibility. The brightness of the light sets are controlled using phase angle firing method, but with the intention of investigating the implementing of a burst firing method.

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Tracking, Dual Rail Power Supply

This article details the construction of a bench top power supply that can be used to power circuits or devices during development work in the lab. More specifically it is an adjustable, tracking, dual rail supply which means there are two supply voltages, one positive, one negative, that are adjusted by a common potentiometer such that supply voltages are equal in magnitude. It is capable of supplying up to +/- 15V DC at up to 1A. This is sufficient for the majority of small signal e... Read more

Remote Control

This is a simple wireless remote control unit, which was originally designed for a model hovercraft which I was developing with the help of my friend Uday Arya. The project has been discontinued for technical reasons, but this remote control unit survives. The method used seems to be quite popular among many remote control units.

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Fun and Games with Transistor Astables

This project is all about fiddling with devices. Often people jump into electronics at the integrated circuit (IC) level, wiring IC's up without much knowledge of what's going on underneath. This project doesn't involve any IC's, just a few discrete components. That doesn't mean it's boring as there's plenty to be gained by building this circuit and having a look at how it works.

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Phase Controlled Lighting System

This project was developed to provide some pleasant room lighting as the author was fed up with inflexible standard incandescent light bulbs used in most rooms. Specifically it details the use of five Low Voltage Lamp units as up-lighters placed around a room. Each lamp can be turned on/off individually and all lamps can be dimmed from full brightness down to zero brightness. Figure 1 shows one of the lamps mounted to a wall.

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