ELC111 Lecture 3 Delta wye resistors.pptx

Wye-Delta formula

1. Wye & delta circuits AND RESISTOR TYPES & COLOR CODE

2. DELTA ( Δ ) & WYE (Y) CIRCUITS

3. DELTA ( Δ ) TO WYE (Y) TRANSFORMATION Each of the resistances in the star or wye is equal to the product of the resistances of the adjacent arms of the delta divided by the sum of three delta resistances.

4. WYE (Y) TO DELTA ( Δ ) TRANSFORMATION Each of the resistances in the delta is equal to the sum of the products of the resistances in the star or wye, taken two at a time, divided by resistance in the opposite leg.

5. https://www.youtube.com/watch?v=SNT5gEcRPSY

6. RESISTANCE OF WIRES – CIRCULAR MILS The American Wire Gauge system for specifying wire diameters was developed using a unit called the circular mil (CM), which is defined as the area contained within a circle having a diameter of 1 mil (1 mil 0.001 inch). A square mil is defined as the area contained in a square having side dimensions of 1 mil.

7. TABLE OF AWG WIRE GAUGE SIZE

8. EXAMPLE: Determine the cross-sectional area in circular mils of a wire having the following diameters: 0.0159 inch SOLUTION: d= 0.0159 inch =15.9mils Therefore, it is a 26AWG wire.   b. 0.0720inch SOLUTION: d= 0.0720 inch =72mils Therefore, it is a 13AWG wire.  

9. VARIABLE AND FIXED RESISTORS All resistors fall into two main categories: Variable and Fixed resistors VARIABLE RESISTORS are type of resistors that could change resistance from zero to a certain maximum value. They are used to adjust the volume of our radios, set the level of lighting in our homes, and adjust the heat of our stoves and furnaces. Terminals of variable resistor Variable resistor used as potentiometer* Variable resistor used as rheostat* *Potentiometer controls the voltage. Rheostat controls the current.

10. VARIABLE AND FIXED RESISTORS FIXED RESISTORS are type of resistors having values that are essentially constant. There are numerous types of fixed resistors ranging in size from almost microscopic (as in integrated circuits) to high-power resistors which are capable of dissipating many watts of power. Other types of fixed resistors include carbon film, metal film, metal oxide, wire-wound, and integrated circuit packages.

11. The figure below illustrates the basic structure of the molded carbon composition resistor and metal film resistor.