This circuit multiplies the frequency of a signal by 100. The circuit was found in the October 1994 issue of Electronics Now magazine. The PLL does not operate above approximately a dozen megahertz.
This circuit protects the speakers in case the amplifiers have problems. With a continuous voltage...
We found this circuit in an American documentation from the 60's. The transistors are made of...
This circuit provides a signal when dialing occurs. The circuit is powered by the telephone line...