This circuit takes advantage of the noise generated at the reverse biased junction of a germanium diode. Other types of diodes can be used. The signal is weak.
With this circuit it is possible to control an operational amplifier so that it switches an input...
This circuit consists of a traditional amplifier version with complementary output using BD series...
This circuit was obtained from a Texas Instruments 1985 document. The circuit is powered by 1.5 V...