This circuit was found in an Electronic Design from the 90s. The circuit uses a type J thermocouple that can measure from -50 to + 100º C. Power is provided by a 3 V lithium battery.
This version is a variation of the previous circuit, inverting the position of the transistors to have the...
A frequency range determined by the network of resistors and capacitors with negative feedback and input...
This circuit was found in an English magazine Radio & Electronics Constructor of February 1977....