This circuit was obtained in a Electronics World of 1968. The transistors can be equivalent as the BC558 for the PNP and the BD135 for the NPN powering lamps from 3 to 12 V according to the supply.
In the figure we show how to trigger a triac for a continuous voltage of the order of 2 V,...
This 2005 Linear Technology circuit has separate outputs for monitoring the charge and discharge...
This circuit was obtained in a June 1987 magazine Hands-On. It is a circuit that indicates on two...