electronic systems,programmablecomponents,mechanical devices

• What are the two main types of electrical measurements in a circuit?

  Voltage and current
• What does voltage measure in a circuit?

  Electrical 'pressure' at a point
• In what unit is voltage measured?

  Volts (V)
• How is current measured?

  In amps (A) or milliamps (mA)
• What does Ohm's law describe?

  The relationship between voltage, current, and resistance
• What is the formula for Ohm's law?

  $V =$$IR$
• How is resistance measured?

  In ohms (Ω), kilohms (kΩ), or megaohms (MΩ)
• What are preferred values in resistors?

  Specific resistance values that resistors are made in
• What is the E12 series?

  A set of 12 standard resistor values
• What is the significance of the E24 series in exams?

  It includes E12 values with additional values
• How are resistor values typically marked?

  With a series of coloured bands
• What does tolerance in resistors indicate?

  How close the actual resistance is to the printed value
• What does a system diagram show?

  Input, process, and output subsystems
• What types of signals can pass between subsystems?

  Analogue or digital signals
• What is the function of a switch in an electronic system?

  To produce a digital input signal
• What is a latching switch?

  A switch that stays on when released
• How does a momentary switch operate?

  It turns off when released
• What is an SPST switch?

  A basic on/off switch with two terminals
• What is the function of a tilt switch?

  It turns on when upright and off when inverted
• What is a reed switch?

  A SPST switch operated by a magnet
• How does the resistance of an LDR change?

  It decreases as light level increases
• What happens to a thermistor's resistance as temperature increases?

  It decreases (ntc type)
• How is a moisture sensor created using LDR or thermistor?

  By using two parallel metal probes
• What is the potential divider formula used for?

  To calculate the output voltage
• What is the function of a transistor?

  To amplify a small signal into a bigger one
• What are the three terminals of a MOSFET?

  Drain (d), gate (g), and source (s)
• When does a MOSFET switch turn on?

  When gate voltage rises above 2.5 V
• What is a thyristor used for?

  To switch on an output transducer with a trigger
• What happens to a thyristor when the trigger signal is removed?

  It stays switched on
• What is the purpose of a monostable circuit?

  To turn on output for a set time
• What components control the time period of a monostable?

  A resistor and a capacitor
• What is the formula for calculating the time period of a monostable?

  $T =$$1.1RC$
• What does a capacitor do?

  Stores electric charge
• How is capacitance measured?

  In farads (F), microfarads (µF), or nanofarads (nF)
• What type of capacitors are usually below 1 µF?

  Ceramic or polyester type
• What is an astable circuit used for?

  To produce a stream of output pulses
• What is the formula for calculating frequency in an astable circuit?

  $f =$$1.44 / (R1 + 2R2)C$
• What is a voltage comparator used for?

  To compare two analogue voltage inputs
• What happens if V₁ is greater than V₂ in a voltage comparator?

  Vout is logic 1 (on)
• What is the role of an operational amplifier in a voltage comparator?

  It compares the values of the two inputs