TTL Counter (CB21360E)

This counter from 0 to 9999 was found in English documentation. The power source must be 5V with at least 1A.

Filter analyzer (CB8227E)
Found in a 90s Popular Electronics, this circuit is interspersed between the filter and the...
RIAA Equalization Amplifier (CB4952E)
This circuit is from an 80's documentation. The integrated circuit is from the time and the...
Undervoltage indicator (CB9580E)
This circuit was found in a 80s American documentation. The zener diodes determine the points of...