Common general purpose silicon diodes when direct biased provide a voltage fall of about 0.6 to 0.7 V. When can use this voltage-fall like in a zener diode. So, two diodes in series are equivalent to a 1.2 to 1.4 V zener. We use this properties in a simple power supply simulated here in the MultiSIM. The output current is up to 50 mA. R1 is a 2 W resistor and value can change according the transformer. Secondary voltage for this transformer is in the range between 3 and 6 V.
To download the simulation files and Netlist - click here (ni0025.zip)
