R1 may be 10k and R2 100k. The transistor can be the BC548 and instead of the small lamp we can use a series LED with a 1k resistor. D1 is germanium and C1 is 10 nF. C2 can be 47 nF.
This circuit is from old documentation, but the regulator may be 78xx series equivalent and the...
This circuit is intended to maintain constant current in a heating element. This element must have...
In the figure we have the way to use the 555 to control loads in the bistable form. The circuit is...