Found in an American publication from 1968, this circuit generates pulses at a rate of 2,500 per second. The transistor can be replaced by a modern equivalent.
This amplifier with gain control was obtained in a documentation from Signetics of the 80's....
The commercial MT2B receiver manufactured in Japan in the 1960s had a listening device only and...
This negative ion generator was found in a 90s Popular Electronics. The autotransformer can be an...