This circuit was found in the November 1974 Radio Electronics magazine. The voltage depends on the supply and the timings of R1 and R2 as well as C1 and C2.
The transistors T1 and T2 of this circuit can be the BC558. T3 can be a BD135 and T4 a TIP42. The...
In the figure we show a means of changing the output voltage of a fixed regulator, such as 7805 or...
We got this circuit in a publication of 1987. This is an audio limiter, a circuit that cuts peaks...