Logarithmic power VU meter

To indicate the power level, I came up with a small driver for the VU meter


Log-amp-for-SO-53.jpg



The amplifier is a chip for hearing aids. The logarithm occurs on the nonlinear characteristic of the diode chain. At the output, a forcing chain is added, which allows the arrow to move quickly forward and slowly roll back.

Gain characteristic:

Log-amp-characteristic.jpg


General view of the structure with the SO-53 VU meter

SO53-log-top.jpg


SO53-log-botton.jpg


There is one drawback, at elevated temperatures, the driver lies, so this driver is of little use in "hot amplifiers" without its own cooling.