Other Types of Circuits

AIM: What are the different types of circuits?

A / B

For each diagram above create a electronic schematic using the appropriate symbols from the reference table.

Make a comparison between the two circuits, A and B

Characteristics / A / B / Sim / Dif

Series Circuit

Based on the data table what is the true about the current in a series circuit?

Q.1. Using Ohm’s Law, determine the resistance of the circuit. How does this compare to any one of the resistors in the circuit?

Develop a formula for determining the total resistance (equivalent resistance) for a series circuit.

Req =Point to Remember:

Q.2. Determine the equivalent resistance for the following series circuits below. Determine the current in the circuit.

Q.3. Using a VIRP chart.

Voltage Drops and the Loop Rule:

A voltage drop is the amount of voltage lost to an electrical device such as a light bulb or resistor.

How does the sum of the voltage drops compare to the total voltage supplied in a series circuit?

Q.3. A 10  resistor and a 30  resistor are connected in series to a battery that supplies 15 volts of potential difference.

a)Sketch the series circuit.

b)Determine the total resistance.

c)Determine the current

d)Determine the voltage drop over each resistor.e) Determine the power supplied to each resistor.

f) Determine the total power supplied to the circuit.

Q.4. Complete the VIRP Chart (show all work is the space provided):

Two series circuits are constructed with three light bulbs (each bulb has a resistance of 100 ohms) and a 4.5 volt battery. The connecting wires have negligible resistance. In circuit b, however, a short wire is connected across the middle bulb. Answer the questions below using the diagrams above.

  1. In which circuit is the current the greatest?
  2. In which circuit are all three bulbs equally bright?
  3. What bulb(s) are the brightest?
  4. What bulb(s) are the dimmest?
  5. What bulbs have the largest voltage drops across them?
  6. What circuit dissipates more power?
  7. What circuit produces more light?
  8. If Bulb 3 were unscrewed (or burned out) in circuit a, what would happen to the other bulbs in the circuit?

Conclusions:

Resistance

/

Current

/

Voltage

Parallel Circuits

Parallel Circuit:

What do you observe about the value of current in a parallel circuit?

Which ammeters are measuring the total current of the circuit?

Since there multiple paths for the current in a parallel circuit, the current is through each resistor. The of the current in the branches is to the total current from the source.

Q.1. Complete the VIRP chart for the circuit above following the questions below.

a)Fill in the current through each resistor.

b)Determine the voltage over each resistor (V = IR).

What do you observe?

c) Determine the total resistance of the circuit (R = V/I).

How does the total (equivalent) resistance of the circuit compare to any one of the resistors? Offer an explanation.

Determining the total (equivalent) resistance in a parallel circuit

CAF:

Req =Point to Remember:

Properties of the current in a parallel circuit:Voltage Drops in a Parallel Circuit:

Q.4. A 12  heater, a 20  hair dryer and a 25  toaster are connected in parallel to a 120-volt source.

a)Sketch the circuit

b)Determine the current flowing through each device.

c)Determine the total resistance of the circuit.

d)Determine the total current used by the circuit.

Q.5. A 9.0 volt battery is connected to 5 resistors, each of 5 ohms and in parallel with one another. Complete the VIRP chart below and then answer the following questions:

a)Using the appropriate symbols, sketch the circuit.

b)What is the total current of the circuit? (I = V/R)

c)What is the current running through each resistor? (I = V/R)

d)What is the power dissipated in resistor #3?

e) How much electrical energy is consumed by this circuit in 40 minutes?

1. Three resistors of 4.0 ohms, 6.0 ohms, and 12 ohms are connected parallel to an applied potential difference of 12 volts. Calculate

  1. The equivalent resistance.
  1. The potential difference across each resistor.
  1. The current through each resistor.
  1. The resistor that dissipates the most power.
  1. The resistor that receives the most energy.

Conclusions:

Resistance

/

Current

/

Voltage

Circuit Segments

Each segment below is connected to a 120 V voltage source. Find the equivalent resistance of each circuit segment shown below. Then, compare the currents through each resistor, the voltage drop across each resistor, and the power dissipated by each resistor.

Segment / Equivalent Resistance / Current / Voltage Drop / Power
1 /
2 /
3 /
4 /
5 /
6 /

In conclusion….

Resistors in series will always have a CURRENT than resistors in parallel.

Resistors in series will always have a EQUIVALENT RESISTANCE than resistors in parallel.

Junction Rule

Determine the current in the mystery wire (??).

A / B / C
D / E / F

The Junction Rule follows the Conservation of Charge Law:

Q.1. For what type of circuit, series or parallel, does the junction rule apply to?

Conclusions:

Combination Circuits

Q.1. Type of Circuit?

a)Determine the total resistance

Step #1: Determine the resistance of the parallel component.Step #2: Determine the resistance of the series component.

(This will be the total resistance.)

b)Determine the current in the circuit (I = V/R)

c)Determine the voltage drop over each resistor (V = IR)?

Q.2.

Type of Circuit:

a)Determine the total resistance

b)Determine the current in the circuit

c)Determine the voltage drop over each resistor

d)Determine the current through each resistor.

e)Determine the power of the circuit.

Q.3. You are given three resistors of 100 ohms each. In the space provided below, construct as many different circuits using these resistors and determine the equivalent resistance of each.

A / B / C / D

Q.4. You are have five 100 ohm resistors to use. In the space provided below, show the arrangement that would give the following equivalent resistances.

25 ohms / 75 ohms / 100 ohms / 67 ohms

a)What would be the largest resistance for the five resistors?

b)What would be the smallest resistance for the five resistors?

Additional Problems

Q.1. a) Determine the current in the given circuit.

Sketch: / Sketch:

Compare the before and after values for V, I, R and P

Comparison between Series and Parallel Circuits

Characteristics / Series / Parallel / Sim / Dif

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© TELJR Publications, 2009