This circuit was found in 1967 Philips documentation. It uses transistors from that time. Transistors can be replaced with modern equivalents.
Radio Electronics magazine published in a 90's issue this simple alarm that can use any general...
This circuit is from the 2005 Linear Technology Application Manual. The circuit must be powered by 5...
We found this circuit in a 1969 General Electric documentation. The circuit uses transistors of the...