Philips Portable Radio

Tubes are great in radios and amplifiers as long as you have plenty of space in your kitchen or living room, not forgetting a nearby AC power outlet. Most people would say that’s because of “them tubes’ inefficiency, you know, the heater current and all that”. True, a medium sized 1950s tabletop radio consumes anything […]

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Grid Dip Meter

Only a handful of components are needed to build an instrument which is indispensable in any RF workshop: the grid dip meter or ‘dipper’. The main function of this clever piece of test equipment is to determine the resonance frequency of unknown tuned circuits within a certain range (typically, 1.5 to 80 MHz). Apart from […]

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Energy Storing Devices

Unfortunately, the sun may not shine just when you need electrical energy. The reverse is also true: energy may not always be required when the sun supplies plenty of it! In addition to the solar cell array, a stand-alone system requires another important component: an electrical energy storage device. The first device that comes to […]

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From Solar Cells to Solar Panels

A single crystalline solar cell supplies a no-load voltage of about 0.6 V, independent of its size. A cell made from amorphous silicon produces a slightly higher voltage of about 0.8 V. Under normal circumstances, i.e., assuming a normal cell size of 10×19 cm, the power output is relatively low at 1.2 to 1.4 Watt. […]

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Simple VU Meter

Most of us have over the years become familiar with the nervously moving pointers or LED bars of the VU (visual unit) meter on the front panel of a cassette tape recorder or mixing panel that indicate the level of the a.f. signal. A simple VU meter circuit can be purchased at various places – […]

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Simple Logic Analyzers for Hobby Constructors

When you are working with digital circuits you have many devices that are connected with digital signals. While each signal when checked with a digital oscilloscope looks OK, the board may still not function as it should. In such case you need a digital logic analyser. Logic analysers are complex devices that sample many digital […]

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