A trigger diode, also known as a bipolar flip-flop or bipolar rheostat, is a special type of diode. Compared to ordinary diodes, trigger diodes have more control methods and higher sensitivity. It can use the change of external voltage or current to adjust the on-on or cut-off state of the device, so as to achieve the control of the circuit.
A trigger diode is composed of three layers of semiconductor material, of which the p-type semiconductor layer sandwiched in the middle is called the trigger layer, and the n-type semiconductor layer on both sides is called the main region. The structure of the trigger diode is similar to that of a normal diode, but the doping concentration of the trigger layer is lower, resulting in a higher resistance in this region.
1. Amplification ability: The trigger diode can amplify the input signal and realize the amplification of the signal.
2. Controllability: Through the current control of the base area, the current in the collector area can be controlled to realize the control of the signal.
3. High-frequency characteristics: The trigger diode has a high frequency response and is suitable for high-frequency circuits.
4. High reliability: The trigger diode has high reliability and stability.
The operating principle of the trigger diode is based on the conductive properties of the p-n junction. When the control junction is in a forward biased state, the trigger diode is in the conduction state and current can flow through the device. When the control junction is in the reverse bias state, the trigger diode is in the cut-off state and current cannot pass through the device.
The trigger diode can control the device by changing the bias state of the control junction with an external voltage or current. When the input signal is applied to the control junction, if its polarity causes the control junction to be in a forward bias state, the diode is triggered to turn on; If the input signal causes the control junction to be in a reverse bias state, the diode cutoff is triggered. In this way, control of the trigger diode can be achieved by changing the polarity and amplitude of the input signal.
Due to their high sensitivity and high speed, trigger diodes are widely used in various electronic circuits, including:
1. Pulse circuit: Trigger diode can be used to build various pulse circuits, such as multivibrators, counters, pulse generators, etc.
2. Voltage control circuit: Trigger diode can be used to build voltage control circuits, such as voltage regulators, voltage comparators, etc.
3. Logic circuits: Trigger diodes can be used to construct logic gate circuits, such as AND gates, or gates, NAND gates, etc.
4. Amplification circuit: The trigger diode can be used to build amplification circuits, such as amplifiers, switching circuits, etc.
In order to ensure the normal operation of the diode, the following detection methods are commonly used:
1. Voltage test: use a multimeter or oscilloscope to measure the forward voltage and reverse resistance of the diode.
2. Current test: use an ammeter to measure the forward and reverse current of the diode.
3. Peak Reverse Voltage (PRV) test: test the maximum reverse voltage that the diode can withstand.
4. Reverse current test: test the leakage current of the diode under the reverse voltage.