Capacitor Power Supply circuit
One of the major problems that is to be solved in an electronic circuit design is the production of low voltage DC power supply from Mains to power the circuit. The conventional method is the use of a step-down transformer to reduce the 230 V AC to a desired level of low voltage AC. The most simple, space saving and low cost method is the use of a Voltage Dropping Capacitor in series with the phase line. IC2 is connected as a differential amplifier and compares the signals at its two inputs. Referring to the circuit diagram : the input comprises a mains switch, fuse, transformer, bridge rectifier and smoothing capacitor (C2). The difference between the inputs is the voltage drop across 'current’ sensor R4. This IC feeds the current sensing input (pin 2) of the L200. P1 in the feedback loop of the 741 is used to vary the output current of the circuit. IC1 must be mounted on a suitable heat sink as it dissipates nearly all the power of the circuit. T...