This FM micro transmitter was found in an 80s spy book. The circuit can work with equivalent FETs and is powered by a voltage of 0.6 to 6 V. Details of the coil are given next to the diagram.
This circuit makes use of a commercial type current transformer. The circuit is from a 2005 Linear...
This circuit provides a linear attenuation of a signal up to 100 dB. The circuit operates with...
The filter shown in the figure can be implemented with general purpose amplifiers like the 741....