This circuit is from Motorola's Linear Interface ICs of 1993. The integrated circuit is not common and the Triac is chosen according to the power of the controlled load.
Found in old Philips documentation, this circuit uses components from the 60's. | Clique na imagem...
The circuit shown uses the LM324, but can be implemented with other operational ones. The source...
Found in Linear Technology documentation, this circuit drains only 70 uA of the monitored circuit....