Function of Adder An adder is the primary computation unit in a digital computer. Few routines are performed by a computer in which the adder is not used. Adders are designed to work in either serial or parallel circuits. Because the parallel adder is faster and used more often, it is covered in more detail […]
Function of Encoder An encoder is a combinational logic circuit that accepts one or more inputs and generates a multibit binary output. Encoding is the process of converting any keyboard character or number as input to a coded output such as a binary or BCD form. Figure 1 shows a decimal-to-binary encoder. Its function is
A shift register is a sequential logic circuit widely used to store data temporarily. Data can be loaded into and removed from a shift register in either a parallel or serial format. Figure 1 shows the four different methods of loading and reading data in a shift register. Because of its ability to move data
A counter is a logic circuit that can count a sequence of numbers or states when activated by a clock input. The output of a counter indicates the binary number stored in the counter at any given time. The number of counts or states through which a counter progresses before returning to its original state
Sequential logic circuits consist of circuits requiring timing and memory devices. The basic building block for sequential logic circuits is the flip-flop. Flip-flops can be wired together to form counters, shift registers, and memory devices. The flip-flop belongs to a category of digital circuits called multivibrators. A multivibrator is a regenerative circuit with two active
All digital equipment, whether simple or complex, is constructed of only a few basic circuits. These circuits, referred to as logic elements, perform some logic function on binary data. There are two basic types of logic circuits: decision-making and memory. Decision-making logic circuits monitor binary inputs and produce an output based on the status of
The bipolar junction transistor is a current-controlled device, while the field-effect transistor (FET) is a voltage-controlled device. The field-effect transistor uses basically no input current. Instead, output current flow is controlled by a varying electric field, which is created through the application of a voltage. This is the origin of the term field effect. The
Operational amplifiers (op-amps) are analog circuit components that require power to operate. They are widely used in amplification and signal-conditioning circuits. The symbol for an op-amp is shown in Figure 1. The symbol is a triangle, with two leads drawn on one side of the triangle, and the third lead is drawn at the apex
Digital circuits are commonly available in two families: transistor-transistor logic (TTL) and complementary metal-oxide semiconductor (CMOS). There are other families, such as emitter-coupled logic (ECL), but they are not as widely used. TTL devices are based on the bipolar junction transistor technology, while CMOS devices are based on the FET transistor technology. Table 1 shows
Most commercial servo drives accept PWM and direction signals as input. Also, many servo drives produce a PWM output voltage signal to the load such as a motor coil instead of a linearly variable output voltage. A PWM signal is a square-wave signal of fixed amplitude and frequency, but the width of the on and