Diodes, the most common devices in electronic products, are also the simplest semiconductor devices. It ownsTwo electrodes,The current is only allowed to pass in one direction,In the opposite direction, there is almost no conduction, which is often referred to as "one-way conductivity" in the electronics industry. Using this basic property, diodes have a wide range of applications:
1. Rectification
The diode allows the current to pass in only one direction, thus converting alternating current, which changes periodically in direction, into unidirectional pulsating direct current.
Step 2: Switch
Diodes can be used as switching devices. When the diode is forward-biased, it allows current to pass through, equivalent to the switch "on" state; When it is reversely biased, it is almost non-conductive, equivalent to the state of the switch "off".
3. Stabilize the pressure
In a specific circuit, such as a voltage regulator diode (also known as a Zener diode), it can provide a stable voltage output. When the voltage in the circuit exceeds or falls below the set value, the regulator diode will start conducting or shutting off, thus keeping the output voltage stable.
4. Voltage clamp
Similar to the principle of voltage regulation, when the voltage exceeds the reverse breakdown voltage of the diode, the diode begins to conduct electricity, and the voltage is clamped at a lower level to prevent excessive peak voltage from damaging other devices, which are often called TVS diodes.
5. Anti-reverse connection
In the loop, a diode is connected in series to obtain a low-cost anti-reverse circuit.
However, this low-cost solution is only suitable for small voltage applications. If the reverse voltage is very large, exceeding the reverse cut-off voltage, it will also breakdown the diode itself, resulting in the failure of the diode, and it will not play the role of anti-reverse connection.
Step 6 Oscillate
In some specific circuits, such as LC oscillators, the diode can be combined with other components to form an oscillating circuit that produces a periodic signal.
7. Continuous flow effect
When an inductor passes a current, it generates an induced electromotive force at both ends. When the current disappears, its induced electromotive force produces a reverse voltage to the devices in the circuit. When the reverse voltage is higher than the reverse breakdown voltage of the device, the device will be broken down.
The continuous current diode is connected in parallel at both ends of the inductor. When the current in the inductor disappears, the induced electromotive force generated by the inductor is consumed through the circuit composed of the diode and inductor, thus protecting the safety of other devices in the circuit.
8. Detection
In radio receiving devices, diodes are used as detectors to extract low-frequency signals (such as audio signals) from modulated high-frequency signals, a process called detection.
9. Signal amplification
Although the diode is not a traditional amplifier, it can realize the amplification of weak signals in some specific circuits by using the forward nonlinear characteristics of the diode. However, this amplification effect is relatively limited, not as transistors, amplifiers.
10. Glow
Light-emitting diode, or LED, is a commonly used light-emitting device. It can efficiently convert electrical energy into light energy, and has a very wide range of uses in contemporary society, such as lighting, flat panel display and so on.