Dynamic analyzer is another name given to a signal follower or signal chaser. This circuit is from an old Argentine publication, using PNP transistors, which can be obtained from scrap metal. You can change the circuit to operate with more modern transistors, mainly by modifying the base polarization resistors. The phone must be magnetic of at least 1k, but a piezoelectric phone with 1k resistor can be used in parallel. The power supply consists of 4 small cells.
