Lab # 4 Parallel Circuits

Transcription

1 Lab # 4 Parallel Circuits Name(s) Obtain an Electro-Trainer and wire it exactly as shown (Be sure to use the 100 ohm resistor) 1) Record the volt drop and current flow for the Switch, the Resistor and the Lamp. (Hint: Use the mv scale for the switch and label amp flow and volt drop on the diagram above) 2) This is an example of which type circuit? A) Series B) Parallel 3) Write out your own definitions of a series circuit (each student should write their own) A) B) 4) Turn ON the lamps and measure the resistance of the 100 Ω resistor using an Ohm Meter. (this is the INCORECT way to measure ohms) 5) Unhook either power or ground and measure the resistor with the ohm meter. 6) Which should you use to measure resistance with an Ohm Meter? A) Use the Ohm meter when the power is ON B) Use the Ohm meter only when the power is turned OFF 7) Will the amp flow change as current passes through resistance? Yes No 8) Will the Voltage change as current passes through resistance? Yes No 9) What causes the voltage to drop across the switch? 10) If you increase the resistance of this circuit, what will happen to the amp flow? Page 1 of 5

2 Re-wire this circuit using a 200 resistor 11) Record the volt drop and current flow for the Switch, the Resistor and the Lamp 12) Replacing the 100 resistor with a 200 resistor increased circuit resistance. What happens to the amp flow when you increased the resistance in a circuit? 13) Why did volt drop change for the switch and lamp when circuit resistance changed? 14) What happens to volt drop for a component if you decrease amp flow through it? 15) When checking for unwanted resistance you should: (circle all that apply) A) Use an ohm meter with the power turned ON B) Usen an ohm meter with the power turned OFF C) Use Volt Drop with the circuit turned OFF D) Use Volt Drop with the circuit turned ON 16) If voltage and resistance are constant, will the amp flow always stay the same through each part of a series circuit? 17) Will the voltage drop always be the same for each load (resistance) in a series circuit? 18) What will raising the amp flow do to the volt drop through any component? 19) What will happen to Amp flow, if you add more resistance in series, to any circuit? Page 2 of 5

3 Re-wire the board to be exactly as shown 20) Record the amp flow and volt drop for the switch and each lamp 21) This is an example of which type circuit: A) Series B) Parallel 22) Write out your own definition of a parallel circuit. (each student should write their own) A) B) 23) How many Watts are being used by the top lamp? Replace the top lamp with a 300 resistor. Draw a diagram of your circuit and label the volt drop and amp flow for each component. Page 3 of 5

4 Add one more lamp to this circuit in parallel, draw a diagram of this circuit, and record amp flow and volt drop for each component. 24) Does the amp flow stay the same in each branch of a parallel circuit? 25) What happens to the voltage drop across each branch of a parallel circuit? 26) Adding resistors in parallel will: (circle all that apply) A) increase total amp flow B) decrease total amp flow Raise the voltage on the board by using the variable control at the top of the board. 27) What will increasing system voltage do to any electric load? (select all correct answers) A) Increase the amp flow through the load B) Decrease the amp flow through the load C) Increase the Volt Drop across the load D) Decrease the Volt Drop across the load Page 4 of 5

5 Wire the board as shown below Unhook the power to the resistors but leave the resistors wired in parallel. 28) Using the Ohm meter measure the resistance of the 300 resistor. Unhook the 300 Ω resistor from the other wires and resistors 29) Using the Ohm meter measure the resistance of the 300 resistor. 30) Which is the proper method when measuring resistance with an Ohm Meter? (mark all answers that are correct) A) Use the Ohm meter when the power is ON B) Use the Ohm meter only when the power is turned OFF C) Isolate the load being measured by unhooking it from the circuit 31) Why do you have to unhook a component from the circuit to measure its resistance? (give two separate reasons) Page 5 of 5