The transistors of this circuit found in an English 1980s documentation may be the modern BC548 equivalents. The circuit is battery powered and the earphone must be crystal.
This circuit uses a unijunction transistor in a different configuration to generate rectangular pulses at...
What this circuit does is generate a signal in a ladder pattern, containing steps in which the...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...