This step of two transistors has a high input impedance due to the use of FET. We can use BF245 for this function and the bipolar can be BC548. The circuit is from an 1975 American documentation.
January 2017 - Through Mouser Electronics Texas Instruments is launching its new zero-drift...
This circuit was obtained from an American documentation from the 50's. It is a Hartley oscillator that...
This interesting shield circuit was obtained from a Poptronics of February 2001. The American...