Consider a thermocouple used as a sensor with a PLC and givi

Consider a thermocouple used as a sensor with a PLC and giving an output of 0.5 mV per C degree. What will be the accuracy with which the PLC will activate the output device if the thermocouple is connected to an analog input with a range of 0 to 10 V DC and using a 10-bit analog - to - digital converter? What will the digital output be for an analog input of 2.5 V? What is the word length for the analog input? What are the standard word lengths used in PLC? Analogue electrical signals are used to represent process variables such as pressure, speed, temperature, flow rate and so on. The instruments produce electrical outputs that are processed into a standard form so that standard equipment can be connected to it such as analogue to digital converters and meters. One standard form is 4-20 mA. Give the other common standard forms used in PLC for I/O interconnection? Why is the minimum in the above standard 4mA instead of 0 mA? Compare the star, bus and ring forms of network and the methods used to avoid problems with messages. What are the functions of (a) PROFILES DP and PROFILES PA, (b) Control Net, and Device Net? A network is said to involve token passing. What does this mean? Do the following Conversions Convert the following binary numbers to denary numbers: 000011, 111111,001101. Convert the following denary numbers to binary numbers: 100, 146, 255. Convert the following hexadecimal numbers to denary numbers: 9F, D53, 67C. Convert the following denary numbers to hexadecimal numbers: 14, 81, 2562. Convert the following hexadecimal numbers to binary numbers: E, 1D, A65. Convert the following octal numbers to denary numbers: 372, 14, 2540. Convert the following denary numbers to octal numbers: 20, 265, 400. Convert the following octal numbers to binary numbers: 270, 102, 673.

Solution

The Miller effect negatively affects the performance of the common source amplifier in the same way (and has similar solutions).When an AC signal is applied to the transistor amplifier it causes the base voltage VB to fluctuate in value at the AC signal. The positive half of the applied signal will cause an increase in the value of VB this turn will increase the base current IB and cause a corresponding increase in emitter current IE and collector current IC. As a result, the collector emitter voltage will be reduced because of the increase voltage drop across RL. The negative alternation of an AC signal will cause a decrease in IB this action then causes a corresponding decrease in IE through RL. The output signal of a common- emitter amplifier is therefore 180 degrees out of phase with the input signal.

It is also named common- emitter amplifier because the emitter of the transistor is common to both the input circuit and output circuit. The input signal is applied across the ground and the base circuit of the transistor. The output signal appears across ground and the collector of the transistor. Since the emitter is connected to the ground, it is common to signals, input and output.

The common- emitter circuit is the most widely used of junction, transistor amplifiers. As compared with the common- base connection, it has higher input impedance and lower output impedance. A single power supply is easily used for biasing. In addition, higher voltage and power gains are usually obtained for common- emitter (CE) operation.

Current gain in the common emitter circuit is obtained from the base and the collector circuit currents. Because a very small change in base current produces a large change in collector current, the current gain () is always greater than unity for the common-emitter circuit, a typical value is about 50