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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