This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
This circuit was found in documentation from the 90s. The operational amplifier admits an...
This circuit was found in a Popular Electronics from the 90's. The frequencies depend on the...
Considering that the speed of light is extremely great which makes us see a lightning flash...