What is active rectification?
Active rectification is the conversion process of alternative current (AC) into a direct current (DC) with very low distortion in low voltage inputs. AC input levels between 0 and 0.7 Volts (V) are a common problem in using silicon or Germanic passive rectifiers. The ideal diode turns on with zero voltage through the anode and cathode. In real circuits, however, the forward voltage across the silicon diode is about 0.7 V and about 0.3 V for the Germani diode.
The use of active rectification is for circuits that process low AC levels, such as specialized detection of amplitude modulation (AM) signals. In AM, the radio frequency carrier (RF) has an average level of peak or envelope that carries modulation or information transmitted to the radio wave. After restoring the carrier, the AM detection circuit is in AM to restore the envelope. If the envelope less than 0.7 V is required and the perimeter of the CTIive rectification is required.
In alternators, synchronous rectification is used instead of active rectification. Synchronous rectification is made possible by synchronous contacts called commutators. When the rotor winding proceeds in positive performance, this rotor winding is quickly connected or commuting to the output terminal. Once its voltage is below a certain positive minimum level, it is disconnected from the output. Several of these windings are used for output, while the rotor is constantly rotating, leading to a DC output without electronic rectifiers.
Active rectification technique can use active devices such as transistors and operating amplifiers. Inverting operational amplifiers with a feedback between the output of operating amplifiers and the inverting input shows near the ideal active characteristics of the rectifier.In the small forward current required to control the diode creates less than 0.01 V, which is a large improvement compared to passive rectification, which requires at least 0.3 V input. When converting electricity, active rectification is not needed due to relatively high voltage. Passive rectifiers that cause voltage loss of approximately 1.4 to 2 volts are acceptable because huge tension margins are available from unregulated voltage sources.
H-Bridge is a very useful circuit configuration. When used with diodes, H-Bridge becomes a rectifier full of wool. DC outputs are taken where the nodes of the anodes and the cathode cathode are connected. When using with transistors, H-Bridge is able to provide two-way load drive, such as a engine or speaker. In active rectification applications, H-Bridge can be used to ensure the necessary signal transformation and impedance transformation more stable circuit operation.