This preamplifier for phonographic capsules using FET was found in 90s American documentation. Consumption is very low. The power can be obtained from the amplifier circuit with which it works.
This circuit from a 1980 publication, converts the temperature sensed by Q1 into a frequency in a...
This oscillator has its frequency controlled by crystal and its frequency can be between 100 kHz...
The author has many books he had written in Eglish (See the Biography) published by famous...