This circuit, which can be used as a shield, was found in a 90s Electronic Design. The circuit uses a diac and the transistor can be general-purpose.
We found this oscillator in a documentation for radio amateurs from the 1970s. The circuit can use...
Many oscilloscopes have high impedance inputs that make it difficult to observe high frequency signals...
This is the receiver for the previous circuit we found in the December 1992 Radio Electronics...