We found this circuit in the 1957 Raytheon transistor application manual. The transistor can be a BC558 and the common 6 V relay, just by using this voltage in the supply.
This instrument was obtained in a documentation for radio amateurs of 1976. The circuit measures...
This circuit decodes FSK signals with frequencies of 1070 and 1270 Hz and can be used in data...
We found this circuit for guitar training in an English documentation from 1989. The components are from...