The circuit is from the 1994 National Semiconductor Linear Applications Handbook but can be implemented with more modern operational amplifiers. The power supply must be symmetrical.
This circuit has an automatic dynamic gain control in a range of 6 dB to 40 dB. We found it in...
This circuit is from a publication from the 50's. Inductive components are critical, and...
The figure shows how to use the LM3900 to drain current from a load of up to 20 mA with the...