Components Expert

How much do you know about diodes?

The simplest semiconductor components, diodes, have an astonishing number of applications. These applications are realized by many practical and unique diode types, which are essential in modern electronic technology. Now let us understand the diode together.

Application of diode

Although there are only two-pin semiconductor devices, diodes have many important applications in modern electronic technology. As we all know, diodes only allow current to flow through the element in one direction.

This allows the diode to act as a one-way valve, keeping the signal where it is needed, or wiring around the component. Although diodes only allow current to move in one direction, each type of diode has a different effect, which makes diodes useful in many applications.

Some typical applications of diodes include:

  • Rectify the voltage, such as converting AC voltage to DC voltage
  • Isolate the signal from the power supply
  • Reference voltage
  • Controlling the size of a signal
  • Mixed signal
  • Detection signals
  • Lighting

Power conversion

An important application of diodes is to convert AC power to DC power. By forming a half-circuit (single diode) or full-wave (four diode) rectifier, one or four diodes can be used to convert 110V household power into direct current. The diode achieves this by allowing only half of the AC waveform to pass through it. When the voltage pulse is used to charge the capacitor, the output voltage appears to be a stable DC voltage with a small voltage ripple.

Using a full-wave rectifier, by wiring the AC pulse, the positive and negative half of the input sine wave is only regarded as a positive pulse, so that the input pulse frequency of the capacitor is effectively doubled, which helps to keep the capacitor charged and provide more stable Voltage to make this process more efficient.

Diodes and capacitors can also be used to generate many types of voltage multipliers to obtain a smaller AC voltage and multiply it to produce a very high voltage output. With the correct capacitor and diode configuration, both AC and DC output are possible.


Demodulation of signals

The most common use of diodes is to remove the negative components of AC signals in order to work with electronic devices more easily. Since the negative half of the AC waveform is usually the same as the positive half, almost no information is lost in the process. Signal demodulation is commonly used in radio as part of a filtering system to help extract the radio signal from the carrier.

Overvoltage protection

Diodes can also be used as protection devices for sensitive electronic components. When used as a voltage protection device, the diode does not conduct under normal operating conditions, but will immediately short-circuit any high-voltage spikes to ground without damaging the integrated circuit. Special diodes called transient voltage suppressors are specially designed for overvoltage protection and can handle very large power spikes in a short period of time. This is a typical feature of voltage spikes or electric shocks, which usually damage components and shorten the life of an electronic products.

Current steering

The basic application of the diode is to control the current to ensure that the current only flows in the correct direction. One area where the diode current control capability works well is switching from power supply to battery operation. When a device is plugged in and charged, for example, a mobile phone or an uninterruptible power supply, the device should only get power from an external power source instead of a battery. When the device is plugged in, the battery should get power and charge. Once the power is disconnected, the battery will power the device, so the user will not notice the power interruption.