We found this circuit in the Linear Applications Handbook by National Semiconductor. It uses the LM3900, an operational transconductance amplifier as a base. Q1 can be a 2N2222 or similar.
This latched alarm uses a double relay for this purpose and can control higher power external...
This circuit was found in an old American documentation on telecommunications. It is suitable for...
Taking advantage of the comparator setting, we can use the Norton amplifier as an over temperature...