This circuit for very low frequencies was found in an American documentation from the 90's. Transistors are for general use and the frequency depends on C1 and C2.
This circuit generates an ultrasound whose frequency is set in P1. Reproduction is done on a...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...
The circuits shown in figure 2 are suggested by Texas Instruments (www.ti.com) make use of the...