# What is the relationship between transistor and gate?

Last Update Time: 2019-11-01 10:22:23

The relationship between transistor and gate.

In fact, it is very convenient to form a logic gate circuit on the motherboard by using transistor and resistance.

As shown in figure 2, it is a very common follow door made up of two transistors on the laptop motherboard and the desktop motherboard.

Between point a and point b is a follow gate.

When a point is high, the CE of NPN transistor Q1 is turned on, and the 2 pins of R pull 1 resistance are short-circuited to the ground after passing through the CE of Q1, which makes the level of c point close to the low level of ground, that is, the base voltage of Q2 becomes low level, Q2 cutoff, and the collector of Q2 outputs V2, that is, point b is high level.

When a point is low, NPN transistor Q1 cutoff, Q1 collector output V (R upper pass 1 resistance 2 pins), which makes the level of c point close to V high level, that is, Q2 base voltage becomes high level, NPN transistor Q2 CE conduction, R upstairs 2 resistance 2 pins after Q2 CE short circuit to the ground, which makes the level of b point close to the ground low level.

The following gate is often used for signal transmission isolation, but also for level conversion (the high-level input from point a is converted to the high level of V 2 after passing through the gate).

In order to deepen the reader's understanding of the door made up of transistor, the author introduces a simple gate chip used by an Apple laptop, as shown in figure 2 (see Chapter 3 / figure 2 of the package for a clear picture).

Figure 2 simple gate chip

Q7950 implements a door-to-door function. The 6 pins are pulled to 3.3V through R7956, and the 5, 7 and 1 pins are the three inputs with the gate. Only when the three inputs are high at the same time, the S pole of the internal integrated N channel field tube Q1 can obtain the high level of the input from the 6 pins (after three C poles of Q2, Q3 and Q4 to the E pole) and output after the Q1 is turned on.

Not strictly speaking, the independent gate chip is actually a bunch of transistors and field tubes. The first T in TTL is the transistor.

If you want to know more, our website has product specifications for transistors, you can go to ALLICDATA ELECTRONICS LIMITED to get more information