SA Practice Parallel Circuits and Circuit Elements
Draw a schematic diagram that contains a 1000 V battery, a 3000 Ω resistor, a 0.5 μF capacitor, and an open switch wired as a series circuit.
Schematics should show all the named circuit elements wired in series, but the order is not important. (C: = R: pointy lines B: one long and one short line)
Why is there a current in the circuit shown in the schematic diagram above?
The circuit has a closed path for the flow of charge.
In a series circuit, one of the resistors is replaced with a resistor having a lower resistance value. How does this affect the current in the circuit? Explain.
The current in the circuit increases because the equivalent resistance is lower than it was before the replacement.
How does the equivalent resistance of a series circuit compare to the resistance values of the individual resistances in the circuit?
The equivalent resistance is greater than any of the individual resistances.
How does the equivalent resistance of a parallel circuit compare to the resistance values of the individual resistances in the circuit?
The equivalent resistance of a parallel circuit is less than the resistance of any single resistor in the circuit.
In the circuit shown above, what will happen when the switch is closed? Explain.
The lamp will go out, or the lamp will get dimmer. The resistance through the switch is lower than the filament of the lamp.
In the circuit shown above, which resistors, if any, have equal voltages across them?
The voltage across Ra is equal to the voltage across Rd, and the voltage across Rc is equal to the voltage across R
Current is not carried in the circuit shown in the schematic diagram above. Explain why this is so.
There is no continuous path for current because the switch is open.
What part of a circuit dissipates energy?
the load
Identify the types of elements in the schematic diagram above and the number of each type.
two batteries, three resistors
Why does the potential difference measured at the terminals of a battery decrease as the amount of current supplied to a load increases?
A battery has a small internal resistance. As the current increases, the potential difference across this internal resistance increases and reduces the potential difference measured at the terminals of the battery.
A voltmeter is used to measure the voltage across a device and is placed in parallel with the device. All voltmeters have resistance. Why would a voltmeter with a high resistance be preferable to one with low resistance when measuring the voltage across a resistor that is part of a complex circuit?
A high-resistance voltmeter would not alter the resistance of the circuit as much as a voltmeter with a lower resistance. Because the resistance of the voltmeter is in parallel with the resistor across which the voltage is being measured, a high-resistance voltmeter will give a more accurate voltage reading than a voltmeter with a lower resistance.
What is used to represent the various parts of the circuit in a schematic diagram?
A schematic diagram uses symbols to represent the various parts of a circuit.
Which bulb or bulbs will have a current in the schematic diagram shown above?
Bulb A has a current, but B and C do not because the switch is open.
You have only six resistors available, and all of the resistors have a value of 10.0 Ω. How would you connect these six resistors to produce an equivalent resistance of 12.0 Ω?
Connect five resistors in parallel to produce a 2.0 Ω resistance and then connect the group in series with the remaining 10.0 Ω resistor. This produces an equivalent resistance of 12.0 Ω.
What is another name for an unintended path for the flow of charge?
a short circuit
What type of circuit has an incomplete path for the flow of charge?
an open circuit
