This oscillator for frequencies up to a few tens of kilohertz was found in a 1970s documentation. The transistor can be of general use. For the component values used, the frequency is 250 Hz.
This circuit was found in a 1987 publication, but it can still be easily assembled today as the...
This circuit uses a common diode as sensor. The output goes from 0 to 10 V with the temperature change in...
This circuit, from an old publication, can also use modern transistors. Note that the unit is...