We found this circuit in an Electronic Engineering of the 90s. The circuit can be implemented with any logic and next to the diagram the truth table for the indications is given.
Suitable for recovering tape recorded media from a common tape player mechanism, this circuit is...
This circuit is indicated to operation with piezoeletric transdicers or other with high impedance...
Of course, the current is extremely small, but a voltage of 300 V can be obtained from 9 V of a...