This harmonic oscillator controlled by crystal was found in an American documentation of the 90's. The circuit uses transistors of the time. Current equivalents can be used.
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...