Archive for the Category


Telephone transmitter with BF494

Saturday, January 30th, 2010

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This is a simple, but very useful circuit that can be used to transmit telephone conversations. When the telephone receiver is on hook the voltage across the lines will be about 48 volts. The preset R7 is so adjusted to obtain a 24.7 V across between the cathode of D2 and ground. At this voltage [...]

145-146 MHz crystal FM Transmitter

Monday, August 3rd, 2009

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This project is a simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood) 2200, PYE, Motorolla, Tait equipment, to name but four. The frequency of the crystal is not critical as almost any other xtal [...]

House fm transmitter 88-108MHz at 4 Watt

Sunday, April 19th, 2009

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This is Fm transmitter circuit for house. It is modulation type Mono FM and Frequency range 88-108 MHz. By it have Working voltage range 12-18 VDC and use current max at 450mA only. This circuit convenient for , because , have good small-sized. It is the ideal project for the beginner who wishes to get [...]