Full-wave rectifier
Can build a bridge or half-bridge circuit (when, for example, in the case of rectification of single-phase current, uses a special transformer with a conclusion from the midpoint of the secondary winding and half the number of rectifying the current elements. This scheme is now seldom used, because more metal and has a larger equivalent active internal resistance, there is a great loss to heat transformer. In the construction of full-wave rectifier with smoothing capacitor should always remember that AC voltage is always measured in the "current" value, which is 1.41 times less than the maximum amplitude, and the rectified voltage capacitor, in the absence of stress, there is always the same amplitude. This means that, for example, when measuring the voltage of a single-phase AC to 12 volt single-phase bridge rectifier with smoothing capacitor, the capacitor (in the absence of load), will power up to 17 volts. Under load rectified voltage will be lower (but not below the current AC voltage, if the internal resistance of the transformer - AC - to zero) and depend on the capacity of the smoothing capacitor.
Accordingly, the choice of the value of alternating voltage secondary winding of the transformer must be built based on the maximum permissible value of supply voltage and capacitance smoothing capacitor - should be large enough to strain under the load has not decreased less than the minimum. In practice also takes into account the inevitable voltage drop under load - a resistance wires, winding of the transformer, diode bridge rectifier, as well as possible deviation from the nominal value of the supply voltage transformer power supply.