CET Circuit Theory and Analysis

Question 1

What is Ohm's Law?

Accepted Answer

V = I * R

Answer

Ohm's Law is a fundamental principle in electronics that describes the relationship between voltage, current, and resistance in an electrical circuit. The formula V = I * R states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, with the constant of proportionality being the resistance (R). This law is essential for analyzing and designing circuits.

Question 2

In a series circuit, what happens to the current as more resistors are added?

Accepted Answer

The current stays the same, but resistance increases.

Answer

In a series circuit, a defining characteristic is that the current is uniform throughout all components, meaning it "stays the same" at every point in the single path. When additional resistors are added in series, the total resistance of the circuit undeniably increases, as resistances add up directly. While this increase in total resistance will cause the overall magnitude of the current from the source to decrease (according to Ohm's Law, I=V/R), the fundamental principle that the current is consistent through each component in the series path remains.

Question 3

What is the purpose of a capacitor in a circuit?

Accepted Answer

Answer

The primary purpose of a capacitor in a circuit is to store electrical energy in an electric field. It does this by accumulating electric charge on its plates. Capacitors can then release this stored energy quickly when required, making them useful for filtering, smoothing voltage fluctuations, timing circuits, and energy storage applications.

Question 4

What is the total resistance in a parallel circuit?

Accepted Answer

The reciprocal of the sum of the reciprocals of the resistances.

Answer

In a parallel circuit, the total resistance (R_total) is calculated differently than in a series circuit. The formula for total resistance in parallel is 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn. This means you sum the reciprocals of individual resistances and then take the reciprocal of that sum to find the total resistance, reflecting that adding more paths for current flow actually decreases the overall resistance.

Question 5

What is a common method for measuring current in a circuit?

Accepted Answer

Answer

To accurately measure current in a circuit, an ammeter must be connected in series with the component or path where the current is to be measured. This ensures that all the current flowing through that part of the circuit also flows through the ammeter. Ammeters have very low internal resistance to minimize their impact on the circuit's current flow and provide an accurate reading.

(CET) Certified Electronics Technician Practice Test

(CET) Certified Electronics Technician Practice Test

CET Circuit Theory and Analysis