# Ch. 2- Resistance Noise MT

Question Answer What is the relationship between resistance and band size? Larger band size= larger resistance What are some differnt types of resisters? (4) 1. Carbon, 2. Metal film, 3. Potentiometer, 4. Themisters In regard to ohms way, what does resistence =? Voltage/ current 1 ohm= 1 volt/. Amp V= I R I= V/R If V is fixed, larger the R… Smaller the I If R is fixed, larger the V Smaller the I? If I is fixed, larger the R Larger the V required to overcome to generate more current True or False- any material has resistence True What does power =? (3) 1. P= VI, 2. P= V^2/R, 3. P=I^2 R Energy that is consumed becomes (3) 1. Light, 2. Mechanical energy, 3. Heat To make current, ________ is needed to overcome resistence Energy Where does energy come from? Voltage– drives charge to move through resister to produce current When resistence is low, and voltage is fixed, equipment will use (more/less) power More If you use a piece of metal wire to connect two holes of power outler/ two poles of battery– what will happen? Short circuit Why? Because resistence will be close to 0, this will make current indefinitely large… will produce a lot of heat… may cause fires What is used as a safety device in most homes to prevent short circuit? Fuse What is an open circuit? Circuit is broken w/ no connect b/w poles –resistence becomes indefinitely large When resisters are in serial, what does the total resistance =? Rt= R1+R2+R3 In a serial circuit, what does current (I)= Voltage/ (R1+R2+R3) In serial circuit, what does the total voltage equal? VR1+VR2+VR3…. sum of voltage drop at each individual resister In serial circuit, what does the individual voltage equal? Vi=I x Ri In serial connection, the current that goes through individual R is (same/different) Same In serial connection, the voltage that goes through each individual R is (same/different) Different– voltage drops down across the pathway In parallel connection, the three resisters/load are driven by the (same/different) voltage? Same In parallel circuit, what is the total current? Summation of individual currents through all branches… It=I1+12+13 In parallel circuit, what is the total resistance? 1/Rt= 1/R1+1/R2+1/R3 How do you calculate individual current in parallel connection? Ii= V/ Ri ** True or False- in parallel circuit, total resistance is smaller than any individual resistance True Why? If you provide more than one pathway, the current can move easier– resistance drops down Smaller resistance= (Larger/smaller) load Larger– more power will be used Most of our equipment is connected in (parallel/serial)? E.g., household equipment Parallel What does this allow? What is the impact on resistance ? Allows each device to receive the same voltage– causes restance to be reduced– total current/power increased *** In serial, bigger resitence uses (more/less) power More power