samy555
Full Member level 4
I have some simple questions about this circuit and I hope to get answers
from: http://www.talkingelectronics.com/projects/27MHz Transmitters/27MHzLinks-1.html
(1) Where is the positive feedback needed to sustain oscillation?
(2)
(3)
(4)
from: http://www.talkingelectronics.com/projects/27MHz Transmitters/27MHzLinks-1.html
(1) Where is the positive feedback needed to sustain oscillation?
(2)
How will I know that the frequency is adjusted? What is the simple way to do that?The frequency is adjusted by a ferrite slug in the centre of the coil until it is exactly the same as the crystal.
(3)
The crystal grounded the base at 27MHz, so the transistor is configured as a common base amplifier?The transistor is configured as a common emitter amplifier.
(4)
I have calculated the reactance of that 82p cap and it was almost equal to 72 ohm. Is not a large value? Why not choose largest value of the capacitor so that it becomes less reactive?It has a resistor on the emitter for biasing purposes but the 82p across the 390R effectively takes the emitter to the negative rail as far as the signal is concerned.