I found tis circuit in na old documentation from 1958. The circuit uses germanium transistor availble that time and hard to obtain today. The circuit is indicated for phono applications using variable reluctance transducer.
The current of this source is 200 mA at the most, and the output depends on the zener that may...
This peak detector has a memory to prolong the response. The circuit is from American...
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...