Low battery indicator 555 (CB9551E)

This circuit can operate with different voltages, depending on the zener used. We found it in a 90s American documentation.

Non-Inverter Amplifier LM675 (CB19036E)
The National Semiconductor LM675 operational amplifier can provide up to 3 A of output current. In the...
Active Tone Control (CB6314E)
We found this circuit in a 1969 Mullard documentation. The same configuration appears elsewhere in...
Timer 555 (CB8111E)
Found in a PE Hobbyst Handbook of 1991, this circuit was originally proposed to time photographic...