This circuit, which can be seen elsewhere on this website, was obtained from a 90’s English documentation. The circuit drives a small speaker, but for greater volume an external amplifier must be used.
This circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook. The...
This circuit, found in Texas Instruments documentation from the 90's, provides a voltage reference of...
We found this circuit in an English documentation from 1995. The components used are common...