Before you test your knowledge about Circuits on Gizmo student Exploration, of course you have to learn more about Circuits. Do not worry as many sites provide information about Circuits. Here we are going to share questions of Gizmo Circuits so that you will be able to find the answer.

**Gizmo Circuits Warm-up**

- Try to click the light switch to turn it to “ON” and what happens?
- Please turn on Show current and choose Electron flow.

A. How does changing the voltage of the battery affect the current?

B. How does changing the voltage of the battery affect the brightness of the light?

- Please remove the wire. What happens?

**Question: What Is Relationship Between Voltage, Current, And Resistance?**

- How do you think improving the resistance in a circuit will be able to affect the current in the wire?
- Please turn the light switch “ON” to start the flow of current. For your information, an ammeter is a device which measures current in Amperes. Then, you are able to drag an ammeter to various parts of the circuit.

A. Is the current the same, or is it changing?

B. What is the current in the wire right now?

- Try to measure the current by using the resistor and the voltage combinations given below.

Voltage |
Resistance |
Current |

10 volts | 10 ohms | |

20 volts | 10 ohms | |

30 volts | 10 ohms |

Voltage |
Resistance |
Current |

50 volts | 20 ohms | |

50 volts | 100 ohms | |

50 volts | 200 ohms |

- What is the mathematical relationship between voltage, resistance, and current?

For note: This equation is called Ohm’s law.

- Now, test your equation with the other combinations of the voltage and the resistance. Also, try to modify the equation if necessary.
- The light bulb is a resistor. Try to place the light bulb in the circuit. After that, use Ohm’s law to discover the resistance of the light bulb. What is it?

**Question: In A Series Circuit, There Is One Path For Charge To Flow. What Are The Properties Of The Series Circuits?**

- Now, turn the light switch “ON” and then observe the light bulb. After that, you are able to replace the wire segments with the new light bulbs.

A. How does each light bulb affect to the others?

B. Try to use an ammeter to measure the current in many parts of the circuit. Is the current the same, or is it changing?

- How do you think the total resistance of the series circuit is calculated?
- Try to make a series circuit with a 10-volt battery and four 10-ohm resistors. Please measure the current.

A. What is the resistance of the circuit?

B. Ohmmeters will measure resistance. Please remove the battery and attach the terminals of the Ohmmeter to the ends of the circuit, where the battery used to be attached. What is the resistance?

- How do you calculate the total resistance of a circuit? Test your rule by using the Gizmo. If necessary, you are able to modify your rule.

- Try to replace the battery. Please turn on the show current, and then you are able to remove one resistor. Why would it be an issue if your household appliances were connected in a series circuit?

**Question: In A Parallel Circuit, There Is More Than One Path Along That Charges May Flow. What Are The Properties Of The Parallel Circuits?**

- Now, you have to turn the light switch “On” and check the light bulb. After that, add two more light bulbs to the circuit, parallel to the first two.

A. How does each light bulb affect to the others?

B. Try to use an ammeter for measuring the current in many parts of the circuit. Is the current the same, or is it changing?

2. How do you think the total resistance of the parallel circuit is calculated?

- Set the battery voltage to 15 volts, now try to measure the current in the parallel circuit with 1, 2, 3, and 4 light bulbs. (In each case, you have to place the ammeter next to the battery). Please use Ohm’s law for calculating the total resistance of the circuit. Record results the following:

Number of light bulbs |
1 | 2 | 3 | 4 |

Voltage |
15 volts | 15 volts | 15 volts | 15 volts |

Current |
||||

Total resistance |

- How would you discover the resistance of a parallel circuit with n identical resistors?

- What will be the total resistance and current in a parallel circuit with a 15-volt battery and three 10-ohm resistors?

The total resistance is:

The current is:

- Usually, household appliances are connected in a parallel circuit. Why do you think it might be an issue if too many appliances are turned on at once?

- Try to determine the total resistance of a parallel circuit when there is a variety of resistors is more complex.

- The total current is equal to the sum of the currents in branch:
- Ohm’s law (V = IR) is able to be rewritten as I = V / R. Please substitute this expression into the equation above:
- For note: Since each branch of the circuit may have a different resistance, we write R1, R2, and so forth. However, the voltage is the same across each branch, so V is used for each term.
- Try to divide each side of the equation by V, and you obtain an expression for the total resistance of the circuit:

- Try to determine the total resistance of each of the below parallel circuits. After that, use the Gizmo to check your answer. You are able to calculate the total resistance from the current and voltage using Ohm’s law, or use Ohmmeter to measure the resistance directly.

A. Parallel circuit with 20-ohm resistor & 10-ohm resistor

B. Parallel circuit with two 20-ohm resistors & 10-ohm resistor

C. Parallel circuit with 15-ohm light bulb & 20-ohm resistor

D. Parallel circuit with two 100-ohm resistors & 20-ohm resistor

E. Parallel circuit with 10-ohm, 20-ohm, 100-ohm & 200-ohm resistor