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RECTIFICADOR DE MEDIA ONDA | EXPERIMENTOS CON EL OSCILOSCOPIO
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RECTIFICADOR DE MEDIA ONDA | EXPERIMENTOS CON EL OSCILOSCOPIO

How to Build a Half-Wave Rectifier

Introduction to the Experiment

  • The video introduces the construction and functioning of a half-wave rectifier using a 1N4007 diode connected in series with a resistor. The goal is to observe voltage readings across the resistor and generator terminals.

Understanding Diodes

  • The 1N4007 diode is characterized by its cathode and anode, indicated by a band on one side, which is crucial for understanding current flow. The diode allows current to pass from anode to cathode but blocks it in the reverse direction due to this barrier.
  • Diodes are primarily used for AC current rectification, which will be demonstrated through experiments with the half-wave rectifier setup.

Setting Up the Circuit

  • A simple circuit is constructed on a proto board with the 1N4007 diode and load resistor in series, powered by a function generator producing a sine wave at 50 Hz frequency (similar to mains electricity). The amplitude set for this experiment is approximately 4 volts.
  • An oscilloscope connected via USB will visualize voltage over time, allowing observation of both input and output signals from the circuit.

Observing Waveforms

  • Initially, the sine wave generated by the function generator is displayed on the oscilloscope, showing perfect sinusoidal characteristics with peak-to-peak voltage of 4 volts at 50 Hz frequency. This serves as our reference signal before introducing any components into the circuit.
  • After connecting another channel of the oscilloscope across the load resistor, it becomes evident that only one half-cycle (the positive cycle) appears while the negative cycle is blocked by the diode, demonstrating its rectifying action effectively.

Analyzing Output Voltage

  • Upon superimposing both waveforms (input vs output), it's observed that there’s a reduction in amplitude after passing through the diode—specifically about 0.8 volts drop due to forward biasing losses within the diode itself. Thus, while input peaks at 4 volts, output reaches only around 3.2 volts post-diode application.
  • The absence of negative cycles confirms that we are indeed rectifying AC into DC; during positive cycles, current flows through while during negative cycles it does not due to orientation against potential difference created by source polarity changes.

How Does a Diode Rectifier Work?

Understanding Diode Functionality

  • The diode creates tension by allowing current to pass only during the positive half-cycle, resulting in zero voltage during the negative cycle.
  • A filter capacitor is connected across the resistance where the yellow signal is measured; it charges during the positive half-cycle and discharges during the negative cycle to maintain voltage.
  • The capacitor continuously charges and discharges, acting as a filter that smoothens out fluctuations in voltage.
  • Initially, there was a fluctuating yellow signal primarily in positive cycles; after connecting the capacitor, a nearly constant DC voltage characteristic of direct current circuits is observed.
  • This process converts an alternating current (AC) sine wave at 50 Hz into direct current (DC), which is essential for electronic circuits.

Practical Applications of Diodes

  • The yellow signal represents what all electronic circuits utilize; thus, power adapters contain rectifiers to convert AC from wall outlets into usable DC.
  • The video concludes with a summary of how diodes allow current flow in one direction and their primary application today: rectifying electrical currents.
Video description

Materiales: -Generador de funciones: https://amzn.to/2WDpTYB -Osciloscopio Hantek: https://amzn.to/2HjbwSE -Breakboard: https://amzn.to/2E9PXn3 -Diodo 1N4007: https://amzn.to/2Eb1NNB -Resistencia: https://amzn.to/2HoT4Ip -Condensador 220 uF: https://amzn.to/2WK8ehM -Clip cocodrilo: https://amzn.to/2JEL20N -Cable generador de funciones: https://amzn.to/2Ht8iMN Uno de los usos más importantes del diodo en nuestros aparatos electrónicos es como diodo rectificador. Estos diodos nos permiten transformar la corriente alterna que tenemos es nuestros enchufes en corriente continua. Por tanto, en todos las fuentes de alimentación de nuestros ordenadores, radios, TV, smartphones...encontramos sistema de rectificación de la corriente. Si quieres sabes cómo funciona un rectificador de media onda...no te pierdas el vídeo.