It is an electronic component used as an electronic switch. Its function is almost the same as that of a mechanical switch.
If we want to activate
, You just need to press the button or use the slide switch to slide. The same is true for transistors. Just for the transistor to activate the switch, it needs the trigger or trigger voltage on the foot.
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In this way, current flows from the collector to the transmitter. According to this information, it is found that a transistor usually has three branches, namely a base, a collector and an emitter.
There are two types of transistors, namely NPN and PNP. The difference between these two types is the type of trigger on the footing. For example, in NPN, if voltage is applied to the base, it will be activated; on the contrary, if it is based on PNP, it will be activated; if it is applied to GND, it will be activated. Therefore, NPN is the opposite of PNP.
There are several ways to determine which is a PNP or NPN transistor. Previously, you had to know the location of the base, collector and emitter legs.
By looking at the placement of the transistor legs in the circuit, you can determine the type of transistor. These transistors can be found in many radio amplifiers. For NPN transistors, the legs are arranged as follows:
1. The emitter usually faces the negative electrode or a voltage lower than the collector voltage.
2. The collector pin is usually in the positive direction, or the voltage is higher than the emitter voltage.
3. If a negative current is provided to the base, the transistor is turned off; if a positive current is provided, the transistor is turned on
The commonly used transistors are c945, a733, tip 31, tip 32, tip 41, tip 42, 2n3055, mj2955. For PNP transistors, how to determine as follows:
1. The emitter is usually towards the positive electrode or higher voltage from the collector.
2. The collector is usually in the negative direction or the voltage is lower than the emitter.
3. If the base is supplied with a positive current, when the negative transistor is turned on, the transistor will turn off. Well, after understanding transistors, Liputan6.com, Tuesday (01/22/2019) will discuss transistor functions, which have been summarized from various sources.
Most control systems use Arduino or other types of microcontrollers and use transistors as switches. For example, use Arduino to control AC relay.
Basically, the Arduino output voltage cannot control the AC relay. Especially if it is directly connected, it will damage the Arduino itself. For this, we need a transistor circuit as a switch.
The common transistor function in the control system is as a DC motor driver or controller. If the transistor is saturated or cut off, the DC motor will be turned off or on. The transistor is not only turned on, but also can be used as a determining factor for the direction of rotation of the DC motor. Whether the motor rotates clockwise or counterclockwise. This circuit is usually called an H-bridge resistor.
There are also two transistors in the flip-flop circuit. The leds in the figure below will alternately open and close positions. The reason why the LED turns on or off or the signal generator in this circuit is caused by the RC in the circuit.
Transistors are also commonly used as current amplifiers in regulator power circuits. Usually, it is used as a power supply for Arduino or other microcontrollers.
For example, the picture below. If there is no transistor, the output voltage of 7805 is 5V. However, his current capacity is about 500mA. This means that if the load exceeds 500mA later, the LM7805 will be damaged.
Basically all logic gates, even memory and CPU are composed of millions of transistors? At least I heard it from Mr. Zulham M. Eng, a lecturer in embedded systems.
For example, the NOR gate is made of only one transistor. After understanding the function of the transistor, there is a commonly used transistor product, the transistor tip 31, which is contained in a PNP transistor.
The specification of the transistor tip 31 has a maximum continuous collector current (lc): 3A. With a maximum collector-emitter voltage (Vce) of 40 V, the minimum base-collector on-state voltage (Vbe) at 1.8 V (MAX), and the maximum collector-emitter saturation voltage at 1.2 V (Vce) ). When using Hfe 50, the bandwidth is 3 MHz and the package is TO-220.
The transistors TIP31 and TIP 32 here form a team, which means that these two transistors are complementary. NPN type transistor TIP31 is used for positive signal amplification, and PNP type transistor TIP32 is used for negative signal amplification.
Therefore, without one of them, the enhancement will not be perfect. Based on the above characteristics and existing solutions, we can conclude that this enhancement is a class AB amplifier. There are many components around the two transistors, including two diodes, whose role is to decompose the signal into a positive signal and then send it to the base of TIP31 and a negative signal to the base of TIP32.
In addition, there is a 2k2 resistor that can be used as a voltage divider for the two bases of the TIP by working with two diodes.