Wednesday 16 February 2011

27MHz TRANSMITTER WITH SQUARE-WAVE OSCILLATOR

27MHzTx-SquarewaveOsc

The circuit consists of two blocks. Block 1is a multivibrator and this has an equal mark/space ratio to turn the RF stage on and off. Block 2 is an RF oscillator. The feedback to keep the stage operating is provided by the 27p capacitor. The frequency-producing items are the coil (made up of the full 7 turns) and the 47p air trimmer. These two items are called a parallel tuned circuit. They are also called a TANK CIRCUIT as they store energy just like a TANK of water and pass it to the antenna. The frequency of the circuit is adjusted by the 47p air trimmer

1 comment:

  1. Looks like you missed details about the two inductors:
    -Ferrite core diameter
    -Cable #?? SWG
    -Inductors longitude.

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