This analog telephone line extension circuit monitors when the line is in use. We found it in the November 1996 Electronics Now magazine.
This circuit is from a 1965 Motorola documentation. The transistors are of the time as is the...
This circuit was found in a 1966 General Electric book. The triac and the day are from that time...
The purpose of this circuit is to modify the sound of organs so that they resemble the sound of a...