Based on an LM36000 OTA this circuit was found in the July 1988 issue of Radio Electronics magazine. It covers frequencies in the range of 45 Hz to 45 kHz.
The basis of this circuit is the HA2400 released at the time. The circuit is from a Radio...
This circuit with TTL output was found in a 1968 EEE. The transistor can be of general use. The...
This circuit can be found in a 1970 Motorola documentation. The circuit can be implemented with general...