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 circuit is from a 1973 documentation. In it we have the way of using a FET as an input of...
This circuit was found in a documentation of the year 1958. The transistors are germanium types...
This circuit of a documentation on very old oscilloscopes uses the first commercial transistor of...