core 2 - p3 Flashcards
(25 cards)
What is the purpose of input blocks in control systems?
Input blocks convert real-world signals (e.g., light, temperature, pressure) into electrical or electronic signals (e.g., voltage, current) that the control system can process. They act as the “sensory” component, enabling the system to monitor environmental conditions.
How are input blocks typically represented in block diagrams?
On the left-hand side, with arrows showing signal flow into the process block.
Name three examples of input devices in control systems.
Light sensors, temperature sensors, pressure sensors.
What is the role of process blocks in control systems?
To modify or manipulate input signals (e.g., timing, comparing, counting).
Name three types of process devices and their functions
-Timers: Maintain signals high/low for set periods.
-Comparators: Compare signals to a reference.
-Counters: Tally incoming pulses/signals.
What is the function of a latch in a control system?
To hold a signal high/low until manually reset.
What logic gate produces a high output only when both inputs are high?
AND gate.
Complete the truth table for an OR gate:
Input A Input B Output
0 0 0
0 1 1
1 0 1
1 1 1
How does a NOT gate function?
Inverts the input signal (high → low, low → high).
What is the primary function of output blocks?
Convert electrical signals back into real-world actions (e.g., movement, sound).
Where are output blocks placed in block diagrams?
On the right-hand side, after process blocks.
Name two examples of output devices in control systems.
Motors, buzzers, lights.
What distinguishes open-loop systems from closed-loop systems?
Closed-loop systems use feedback to adjust outputs; open-loop systems do not.
Give two advantages of closed-loop systems.
Higher accuracy and resistance to disturbances
What is a transfer function in control systems?
A mathematical representation of a system’s input-output relationship (e.g., G(s) ).
What is the purpose of pulse width modulation (PWM)?
To encode signal amplitude by varying the width of carrier pulses.
How does pulse amplitude modulation (PAM) work?
Encodes data by varying the amplitude of carrier pulses.
What is the key difference between analogue and digital signals?
Analogue signals are continuous; digital signals are discrete (e.g., 0s and 1s).
Name two advantages of digital signals over analogue.
Easier to transmit, less noise-sensitive.
What do system block diagrams illustrate?
The flow of signals between input, process, and output components.
How do schematics differ from wiring diagrams?
Schematics use symbols for components and connections; wiring diagrams show physical layout.
What standard governs circuit symbols in schematics (e.g., BS 3939)?
British Standard 3939 for graphical symbols.
What is the main limitation of schematics?
They do not show physical component placement.
Give an example of a closed-loop system application.
Temperature control in heating systems.
