This two-tone alarm siren was found in the January 1975 issue of Radio Electronics magazine. The power transistor can be changed and with it, Rx has values from 10 to 47-ohm.
This circuit was found in a European documentation from 1964. The circuit makes use of components of...
This circuit consists of a design improvement that we have previously published (1982), obtaining a new...
This adjustable circuit from 0 to 200 nA was found in a 90's EDN. The components can still be...