TTL Counter (CB21360E)

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

8 Digit Password Coded Lock (CB17980E)
This circuit was found in a publication in 2002 and can be powered by voltages from 5 to 12 V. The...
Gate Dip Meter (CB5175E)
Found in an American 80's documentation, this circuit can use common FETs like the BF245 and cover...
60 kHz ferrite antenna (CB6981E)
Found in a publication for radio amateurs from the 1980s, this circuit amplifies signals in the 60...