As mentioned before, in * circuit analysis*, the currents in a circuit are always assumed to be constant. This allows you to analyze the circuit as if all of the components were replaced with ideal components such as resistors, wires, and batteries.

Circuit analysis is a very useful tool that allows you to analyze a circuit without having to consider all of the individual voltages and currents within it. You can find out how many volts and amps a *particular device needs* by calculating the voltage and current at the entrance point of that **device using circuit analysis**.

Once you have analyzed the circuit, you can then actually test it by measuring the actual voltages and currents within it. This will show you whether your calculations were correct or not.

In this article, we will discuss some general tips for ranking the circuits based on the current through the battery immediately after the switch is closed.

## Circuit #2: 2.0 amps through battery

The next circuit you can test is the circuit that has a battery with 2.0 amps through it immediately after the switch is closed. This means that the current flowing through the battery and circuit is only measured after the switch is closed.

This test requires a *higher current* than the *first one* because now there is a battery involved, and the circuit needs to complete its purpose—to charge the gadget.

Circuit #2 checks to see if the wires are intact, the socket is functional, and the gadget charges. You can also check to see if the **device turns** on by using it. If it does not turn on, then you need to check further down the line to see what may have been missed.

## Circuit #3: 3.0 amps through battery

The third circuit is similar to the second circuit in that it also has a constant current through the battery. The main difference is how long the current flows through the battery.

In this case, the current flows for a few seconds before the circuit is closed. Then, it closes and remains closed for a few more seconds until the **new perfume bottle falls** off and breaks the connection.

At that point, the circuit opens and re-opens quickly, which causes the fan to **stop working**. How interesting!

This is a funny prank to play on someone, especially if they are not aware of how this works. They will **think something** is wrong with the fan or their **smell bomb** so they will take it down to check it out- only to find out it was the prank later.

## Circuit #4: 4.0 amps through battery

The *fourth circuit takes* the battery voltage and multiplies it by the number of amperes flowing through the circuit. The result is the voltage across the battery multiplied by the current flowing through it.

Circuits can be nested, so you could have a fourth circuit that has a certain current through it, and then within that circuit there is a second circuit with a certain current, and then within that second circuit there is a third circuit with a certain current.

All of these currents combine to form the ** total current flowing** through the fourth circuit. Once you know the total current, you can find out how much energy was used by multiplying by the time period it was used in.

This is very important: You have to **rank circuits based** on the current immediately after the switch is closed.

## Circuit #5: 5.0 amps through battery

This circuit shows the battery being drained at a steady rate of 5 amps. The graph shows that the * current drops slowly* as the battery is drained, and it takes a while for the battery to be fully discharged.

Circuits #4 and #3 are similar in how quickly the current drops, but Circuit #3 has a higher current through the battery initially. This means that it *takes less time* for the battery to be fully discharged!

Circuit #2 shows a **sudden drop** in current, which means that part of the circuit was likely covered up or no longer functioning. This could have been done on purpose or by accident due to something happening with the device.

Circuit #1 shows no current going through the battery, meaning that something must have stopped the flow of charge. This could have been done on purpose or by accident due to something happening with the device.

## Circuit #6: 6.0 amps through battery

This circuit includes a battery and a lightbulb. When the switch is closed, the *current must go* through the whole circuit to the other side.

The **current must first pass** through the battery to get to the bulb. The battery output is rated in amperage, or how much current it can output.

A higher amperage battery will allow more current to pass through to the bulb, lighting it up faster.

Then, the *current must travel* through the wire back to the switch, where it returns to its original source. The amount of current in the wire depends on what type of wire it is and its thickness. Thinner wires allow more current to pass through.

These six circuits all have different components, so they will not all function in exactly the same way.

## Circuit #7: 7.0 amps through battery

This **circuit includes** a battery and a switch. The *circuit also includes* a load, in this case, a lightbulb. When the switch is closed, the current begins to flow through the circuit.

The amount of current that flows in a circuit is dependent on *two things*: the voltage of the battery and the resistance of the rest of the circuit (the wire and the lightbulb).

Voltage is how much energy is *transferred per unit* of charge. Resistance refers to how much opposition there is to the current.

The more resistance there is, the less current will flow. When there is no resistance, then there is no difference in voltage, so all of the battery’s energy will be transferred to your load.

## Circuit #8: 8.0 amps through battery

This circuit includes a battery and a lightbulb. When the switch is closed, the *current must go* through the entire circuit before returning to the source.

The **current must first go** through the battery, then through the connecting wire, then into the bulb itself, and then back out of the bulb back into the wire to return to the source.

The amount of current that can flow through a circuit is defined as amperes, or amps (pronounced am-peez). The letter “A” stands for voltage, which is defined as **force per unit** of length.

Therefore, one amp is *one volt per second —* how much force (voltage) passes through an area of one square meter in one second. Circuits are defined by how many amps can pass through them safely.

## Circuit #9: 9.0 amps through battery

The *last circuit tested* is the circuit where the battery is completely discharged. In this circuit, the battery is connected to a wire and a ** metal plate**.

When the switch is closed, there is no current flowing through the circuit. This means that there is no current going through the wire and onto the metal plate. There is no effect on the lamp at all.

Circuits that do not have a functioning battery do not have an effect on a lamp. Only circuits with **functioning batteries** have an effect on a lamp by lighting it up.