Greinacher Voltage Doubler Rectifier Lab Report

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Both Design 2 and Design 3 circuits uses the concept of voltage doubler rectifier in particular the Greinacher voltage doubler rectifier, where the components used are mainly capacitors, diodes. Light emitting diode (LED) and 3-turn coil are also incorporated into Design 2 and Design 3 circuits.

There are two main reasons of using a voltage doubler rectifier. Firstly, the LED require a forward voltage of 1.7V to 2.2V, and the 3-turns coil on the implant will not be able to pick up that much AC voltage, thus a voltage doubler rectifier is used to double the peak of the AC voltage. Secondly, since the received voltage by the 3-turn coil is AC, using the voltage doubler rectifier will then convert the AC voltage to DC voltage and thus allowing constant powering of the LED.
Voltage Doubler Rectifier

The voltage doubler rectifier produces a DC output voltage that is almost doubled the peak of the AC voltage under a loaded condition [4]. The operation of the Greinacher doubler rectifier as shown in Figure 16 will be described with reference to Ray, S [4] for loaded and unloaded condition. Figure 16. Greinacher Voltage Doubler Rectifier [4]
Under No-load Condition

Point O’ is one side of the terminal of the high tension winding of the transformer
The 2-stage voltage doubler rectifier is an extension of the Greinacher voltage doubler rectifier, which is also known as the Cockroft-Walton multiplier [4]. Cockroft-Walton multiplier is formed by a ladder network of capacitors and diodes, in which the n-stage Cockroft-Walton multiplier is obtained by cascading a number of diode-capacitor stages with each stage containing two capacitors and two diodes [5]. Under no load condition, the n-stage Cockroft-Walton multiplier can provide a DC output voltage of magnitude 2nVp where Vp is the peak of the AC voltage