The bipolar junction transistor (BJT) is a device used in digital electronics. It highlights the significance of analog and digital electronics by introducing the concept of Boolean algebra. Special topics include: | bipolar junction transistor | digital electronics | bipolar | junction transistor} Bipolar Junction Transistor Design. The invention of the bipolar junction transistor changed the face of digital electronics. Before its birth, many devices had to use crystals in their operation. But the invention of the bipolar junction transistor changed all that. It became possible to use electronic components in the form of a resistive or an inductive input when they were coupled with a suitable reference source, which is a component that provides current only when the output is demanded.
Diagram of a Bipolar Junction transistor. To design a bipolar junction transistor, you need to draw a model using a potentiometer in figure 3. A thin vertical line connects the inputs, whereas a dotted line connects the output terminals. You have to make sure that the input terminals are in fact in a high value, if they are in figure 3, so that the transistor will respond immediately (transistors will act like a pull-up if the current is high).
Figure 3. The input terminals of a bipolar junction Tapped switch. The collector will draw a 0.5 volt drop across the resistive input. This will be amplified by the Tapped switch’s potentiometer. Then the gate will close down and this will cause the buffer to be charged. The input signal on the input terminals will be inverted when this happens, due to the gate now being closed, and it will now be possible to read the value of the capacitor at the rear of the Tapped switch.
The collector’s gate also has a negative bias, which will push the value of the capacitor to -12 V, or even more. The gate acts as a pull-up on the base of the transistor. When the current flows, the gate becomes close to the ends of the transistor, where it will cause a current which passes through the input terminals. The gate is now in place which will allow the current to move either way. If you have a high current, the current will go through the capacitor, and if you have a low current, the current will go through the resistor.
For a digital logic gate to work correctly, there are some important ground states. For example, the current does not have to go through any gates; in fact, one of the most common mistakes people make is to place a bipolar Tapped switch in a logic state where a bipolar Tapped switch is designed for a different gate. Digital logic gates are used in digital electronics to allow a computer to use a simple program to perform many different tasks.
There are three types of transistors. You will find them in figure 5. The most commonly found type of transistor is the Bipolar Junction Tester (BST). The other two types are the Diode and the Pulse Width Modulator (PDM). You can think of the ST as a gate that is “stuck” open; the PST is one that will “get stuck” or close as a result of the logic signal that is generated. In a sense, the ST is a simple analog device that can be used to test how a diode or a pulse width modulation would respond.
When the input signal passes through the BST, the gate will become closed; however, when the output current is applied to the input terminals, the gate will become open. To determine which condition the transistor is in, the terminals of the transistor will either become very hot or very cold. When the input and output voltages are plotted against the control voltages, the slope of the vertical line will slope away from the control value. A bipolar junction transistor will behave in this manner when the supply voltage is low. The slope of this line is an indication of whether the transistor has closed or opened its terminals.