R2 (and C1) are supply decouplers to the noise generator transistor. Without them there's a good possibility the unit would be unstable, as supply variations would be fed back from the output to the input.
The point of the circuit is that the BC547 is reverse biased and the b-e junction is in zener breakdown which generates noise.
The transistor could be replaced by a zener diode which would probably be just as effective.
The point of the circuit is that the BC547 is reverse biased and the b-e junction is in zener breakdown which generates noise.
The transistor could be replaced by a zener diode which would probably be just as effective.
It would be interesting to compare the noise levels from a transistor version and a zener version, I wonder if transistor 'zeners' are perhaps more noisy? - it seems common to use them in place of a zener in noise generators, but it might just be for convenience?.
It would be interesting to compare the noise levels from a transistor version and a zener version, I wonder if transistor 'zeners' are perhaps more noisy? - it seems common to use them in place of a zener in noise generators, but it might just be for convenience?.
hi, in this arrangement how to compute the gain of 2N3904 and BC549B
I have a problem with the transistor TR3 (which is identical with TR2), R5 linked core and collector at the same time, I can not find the equivalent diagram for calculating the gain, please help me