Basic Electronics for Automation Engineering

Basic Electronics for Automation Engineering Student Name : KasemsunBoonpokkrong Student ID : 53010139 Program : Automation Engineering Homework no. : 2 Date of Assignment : June 7,2011 Date of Submission : June 12,2011

1.AND Gate vs. NOR Gate ? AND Gate A Logic AND Gate is a type of digital logic gate that has an output which is normally at logic level "0" and only goes "HIGH" to a logic level "1" whenALL of its inputs are at logic level "1". The output of a Logic AND Gate only returns "LOW" again when ANY of its inputs are at a logic level "0".

The logic or Boolean expression given for a logic AND gate is that for Logical Multiplicationwhich is denoted by a single dot or full stop symbol, (.) giving us the Boolean expression of: A.B = Q. Then we can define the operation of a 2-input logic AND gate as being: "If both A and B are true, then Q is true"

NOR Gate TheLogic NOR Gate or Inclusive-NOR gate is a combination of the digital logic OR gate with that of an inverter or NOT gate connected together in series. The NOR (Not - OR) gate has an output that is normally at logic level "1" and only goes "LOW" to logic level "0" when ANY of its inputs are at logic level "1". The Logic NOR Gate is the reverse or "Complementary" form of the OR gate.

The logic or Boolean expression given for a logic NOR gate is that for Logical Multiplication which it performs on the complements of the inputs. The Boolean expression for a logic NOR gate is denoted by a plus sign, (+) with a line or Overline, ( ‾‾ ) over the expression to signify the NOT or logical negation of the NOR gate giving us the Boolean expression of: A+B= Q. Then we can define the operation of a 2-input logic NOR gate as being: "If both A and B are NOT true, then Q is true"

2.Half Wave Rectifier vs. Full Wave Rectifier ? Half Wave Rectifier. Wave in a half wave rectifier circuit passes just one half of each complete sine wave of the AC supply in order to convert it into a DC supply.

During each "positive" half cycle of the AC sine wave, the diode is forward biased as the anode is positive with respect to the cathode resulting in current flowing through the diode. During each "negative" half cycle of the AC sine wave, the diode is reverse biased as the anode is negative with respect to the cathode therefore, No current flows through the diode or circuit.

Full Wave Rectifier circuit two diodes are now used, one for each half of the cycle. A transformer is used whose secondary winding is split equally into two halves.Thisconfiguration results in each diode conducting in turn when its anode terminal is positive with respect to the transformer centre point C producing an output during both half-cycles

When point A of the transformer is positive with respect to point C, diode D1 conducts in the forward direction as indicated by the arrows. When point B is positive (in the negative half of the cycle) with respect to point C, diode D2 conducts in the forward direction and the current flowing through resistor R is in the same direction for both half-cycles. As the output voltage across the resistor R is the phasor sum of the two waveforms combined, this type of full wave rectifier circuit is also known as a "bi-phase" circuit.

3. Clipping vs. Clamper ? Clipping circuits (also known as limiters, amplitude selectors, or slicers), are used to remove the part of a signal that is above or below some defined reference level. We’ve already seen an example of a clipper in the half-wave rectifier – that circuit basically cut off everything at the reference level of zero and let only the positive-going (or negative-going) portion of the input waveform through.

Clamping circuits, also known as dc restorers or clamped capacitors, shift an input signal by an amount defined by an independent voltage source. While clippers limit the part of the input signal that reaches the output according to some reference level(s), the entire input reaches the output in a clamping circuit – it is just shifted so that the maximum (or minimum) value of the input is “clamped” to the independent source.

Reference http://coe.uncc.edu/~dlsharer/ETEE3211WebCT/SectionB_pdf/B8.pdf http://www.electronics-tutorials.ws/logic/logic_6.html http://www.electronics-tutorials.ws/diode/diode_6.html

Basic Electronics for Automation Engineering