This circuit is from an American documentation from 1975. The single junction transistors can be 2N2646 and the signal must be applied to the input of a good amplifier.
This circuit was obtained in Linear Technology documentation from 1993. The circuit provides 3.3 V and...
This circuit is from the National Semiconductor CMOS manual of 1977. What this circuit does is to...
This circuit operates from 25 to 65 kHz depending on the transducer used and the settings. We...