Low battery indicator (CB9133E)

This circuit was found in Maxim's documentation from the 80's. The integrated circuit is from that time, uncommon today.

Transformer Coupled AC Switch (CB25075E)
This triac circuit was found in the October 1987 Radio Electronics magazine. The triac is...
Temperature Sensitive Touch Switch (CB10236E)
This circuit was found in a 1987 edition of the United States' Hands-On Electronics magazine. The...
Precedence Detector (CB24358E)
We found this TTL circuit with the 7400 in the January 1975 Radio Electronics magazine. The power...