This TTL circuit is from a Radio Electronics magazine from February 1973. The circuit must be powered with 5 V and the maximum frequency depends on the TTL integrated circuit.
In the figure we have a basic PLL circuit with the LM567 or equivalent. The circuit is from a 1977...
This circuit was found in a documentation for radio amateurs from the 70s. The integrated circuits...
The LM11 is a precision operational amplifier from National Semiconductor. The circuit was found in...