Test your analog electronics knowledge with this engaging quiz featuring ten easy questions on key concepts like op-amps, filters, diodes, and transistors. Perfect for learners seeking to refresh or validate their understanding of analog circuits and basic device behavior.
If a 10 ohm resistor has a current of 2 amperes flowing through it, what is the voltage across the resistor?
Explanation: Using Ohm's Law, voltage equals resistance times current, so 10 ohms times 2 amperes equals 20 volts. The other options are incorrect: 5 volts and 8 volts do not match the calculation, and 12 volts is a common wrong answer when confusing current with power. Only 20 volts correctly applies Ohm's law to this situation.
What happens to the current in a standard silicon diode if the applied voltage is less than 0.7V in the forward-biased direction?
Explanation: A standard silicon diode requires at least about 0.7 volts forward voltage before it conducts significant current. If less than 0.7V is applied, only a tiny leakage current flows. The current does not reach maximum, the diode will not be damaged, and the current doesn't reverse direction as suggested by the other options.
Which device is primarily used to amplify weak electrical signals in analog circuits?
Explanation: Transistors are widely used for amplifying weak signals in analog electronics because they can control a large current with a smaller one. Resistors control current but do not amplify, diodes control the direction of current, and inductors store energy but do not amplify signals. Thus, only 'transistor' is correct.
In the ideal case, what is the input impedance of an operational amplifier (op-amp)?
Explanation: An ideal operational amplifier has infinite input impedance, meaning it draws no current from the input source. Zero and 100 ohms are much too low and would load the previous stage significantly. While 1 megaohm is high, it is still finite; only 'infinite' matches the ideal specification.
When a capacitor is connected to a DC voltage source through a resistor, what does the voltage across the capacitor eventually become after a long time?
Explanation: Over time, a DC-charged capacitor will reach a voltage equal to the source voltage as it fully charges. Zero volts and half are only possible during charging or with different circuit arrangements, and double the voltage would violate conservation of energy. Therefore, 'equal to the source voltage' is the only correct answer.
Which type of analog filter allows signals below a certain cutoff frequency to pass while blocking higher frequencies?
Explanation: A low-pass filter allows frequencies below its cutoff point to pass and attenuates higher frequencies. High-pass filters do the opposite, band-stop filters block a specific band, and 'peak-pass filter' is not a standard term. The correct choice is low-pass filter.
In a bipolar junction transistor (BJT), which terminal controls the amount of current between the other two terminals?
Explanation: The base terminal of a BJT controls the current flow between the collector and emitter. The collector and emitter are the other circuit terminals, and the term 'gate' is used for field-effect transistors (FETs), not BJTs. Therefore, 'base' is the correct answer.
What is the primary purpose of a Wheatstone bridge circuit?
Explanation: The Wheatstone bridge is a network of resistors used to measure unknown resistances very accurately. It is not used to amplify voltage or store energy, and it does not specifically block AC signals. Only the first option matches the main function of a Wheatstone bridge.
What distinguishes an analog signal from a digital signal in electronics?
Explanation: Analog signals are continuous and can assume any value over a range, while digital signals are restricted to distinct values, commonly high or low. The speed, power, or type of wiring are not defining characteristics; these distractors misrepresent the fundamental difference.
To light an LED correctly in a basic circuit, which terminal must be connected to the positive supply?
Explanation: The anode of a Light Emitting Diode (LED) should be connected to the positive voltage, while the cathode connects to the negative side. 'Emitter' and 'source' are terms from transistor devices, not diodes or LEDs. Only 'anode' is the correct answer for proper LED operation.