Found in an RF Design from the 90's this circuit is intended for crystals of less than 1 MHz. Transistors are types of general use today.
This simple audio signal tracer or follower can be made with a BC548 instead of the original...
The circuit shown in figure 1 is a suggested application for ISL8107, a new integrated circuit from...
This notch filter or reject filter rejects signals of a certain frequency with good selectivity. The...