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Posts Tagged ‘Crystal Radio’

Crystal Radio (and other purpose) Audio Amplifier

Here is a simple audio amplifier using a TL431 Shunt Regulator Circuit. The amplifier will provide room-filling volume from an ordinary crystal radio outfitted with a long-wire antenna and good ground. The circuitry is similar in complexity to a simple one-transistor radio but the performance is superior (with the exception of the amazing one-transistor reflex ). The TL431 is available in a TO-92 package and it looks like an ordinary transistor so your hobbyist friends will be impressed by the volume you are getting with only one transistor and the amplifier may be used for other projects, too. Higher impedance headphones and speakers may also be used. An earphone from an old telephone will give ear-splitting volume and great sensitivity! The 68 ohm resistor may be increased to several hundred ohms when using high impedance earphones to save battery power.

Read More Source:http://www.techlib.com/electronics/audioamps.html

Be the first to comment - What do you think? Posted by admin - July 1, 2009 at 7:23 am

Categories: Power Amplifier Tags: basic amplifier, Crystal Radio

Low-Frequency Crystal Controlled Oscillator

The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly. This is a difficult piece of equipment to find and the engineer often has to consult an electronic circuits handbook for the schematic of a circuit that will perform the task.

Unfortunately, there aren’t many such circuits in the technical literature currently available, and when found, they don’t always work as expected. A circuit that has been found to work at full satisfaction in the frequency range from 10 kHz to 500 kHz is illustrated in Figure 1.

Read More Source:Ramn Vargas Patrn

http://www.mitedu.freeserve.co.uk/Circuits/rf/cco.htm

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