This circuit from Ferranti was released in 1969. It makes use of the company's transistors that admit current equivalents. The input voltage is 30 mV for total deflection. The band pass is 800 kHz.
We found this logic level tester in a 1976 documentation. The circuit is powered by the voltage of the...
With this name the LED effects circuit presented was found in the Electronics Now magazine of...
Found in an 1868 Mullard documentation this circuit has a dynamic range of 10 Hz to 25,000 Hz....