Resistance

By:Brandon B, Marc G & Aaron M Chapter 4: Resistance


 * __ Summary __**

Resistance is opposition to current flow. It is inverse to current. The unit of measure is ohms and is represented by “R” and the Greek symbol Omega. The opposite of resistance is conductance. Factors that determine resistance are length, size, and temperature. Resistors can be either fixed or variable. To measure resistance, you use an ohmmeter. Resistors can be connected in series, parallel, and series-parallel.


 * __ Formulas __**

Ohms Law: R =E÷I Resistors in series: sum of all resistors Resistors in parallel: product÷sum; value÷number

Resistance-Resistance is the opposition to current flow. Ohm-unit of measure for resistance. Conductance-Ease of current flow. Potentiometer-has three terminals.
 * __Vocab__**

2nd # || Band3 Multiplier || Band4 Tolerance ||
 * __Resistor color code__** [[image:1k_resistor.jpg width="251" height="219" align="right" caption="1k ohm resistor + or - 5%"]]
 * color || Band1 1st # || Band2
 * Black || 0 || 0 || 1 ||  ||
 * Brown || 1 || 1 || 10 ||  ||
 * Red || 2 || 2 || 100 ||  ||
 * Orange || 3 || 3 || 1,000 ||  ||
 * Yellow || 4 || 4 || 10,000 ||  ||
 * Green || 5 || 5 || 100,000 ||  ||
 * Blue || 6 || 6 || 1,000,000 ||  ||
 * Violet || 7 || 7 || 10,000,000 ||  ||
 * Grey || 8 || 8 || 100,000,000 ||  ||
 * White || 9 || 9 || 1,000,000,000 ||  ||
 * Gold ||  ||   || 0.1 || + or - 5% ||
 * Silver ||  ||   || 0.01 || + or - 10% ||
 * NoBand ||  ||   ||   || + or - 20 % ||

Formula: Rt=R1+R2+R3etc 1k+2k+18k=21k Rt=21k ohms ELECTRON OPPOSITION-This section is basically introducing you to resistance. RESISTIVITY-This section is about what determines a resistors resistivity. CONDUCTANCE-This section is all about what conductance is.Conductance is the ease of current flow. FACTORS DETERMINING RESISTANCE-Length,Cross-sectional area,and temperature all determine RESISTANCE. RESISTORS-This section is all about the types of resistors. -**Wire wound -Carbon Composition -Deposited Film VARIABLE RESISTORS-Potentiometer,and Rheostat.**
 * __Finding resistance__**
 * __CHAPTER SUMMARIES__
 * RESISTOR RATINGS-This section explains the bands on a resistor.