This detector with ultra-low deviation was found in an American documentation from the 90s. Operational amplifiers are from that time. The power supply must be symmetrical.
This other high stability thermocouple amplifier uses an 80's operating. The circuit can be used...
This circuit is from a 1982 publication. It is a sequential effect of accelerated and intermittent LEDs....
Found in a Popular Electronics from the 90s, this circuit presents the difficulty of obtaining the...