MECHATRONICS LATEST 2026 QUESTIONS AND
SOLUTIONS RATED A+
✔✔Integrator amplifier - ✔✔G = -1/(jwCR) = -Zf/Z1 = -Vout/Vin
Vout = 1/(RC) x intergrate V dt
✔✔Low-pass filter - ✔✔G = -(R/R1) x 1/(1+ jw/w0)
✔✔S-R latch - ✔✔have memory of the last button pressed
✔✔Single-shot delay timer - ✔✔Change value of their output after a certain period of
time has elapsed since the timer was enabled
✔✔Coulomb (electromagnet) - ✔✔F = kq1q1/(r^2)
✔✔Faraday law - ✔✔the magnetic flux flowing through a closed surface is equal to the
integral over the whole surface of the scalar product of the field gradient and the normal
to an infinitesimal surface element
✔✔Lorentz - ✔✔F = qE + qv x B
✔✔PMDC - ✔✔F = ilB
T = 2ilBa = ki
Vb = 2alBw = kw
✔✔Stall torque - ✔✔No speed torque
✔✔Armature resistance - ✔✔i^2 R
✔✔Motor Power, P - ✔✔P = torque x w = iVb
✔✔Motor peak power - ✔✔efficiency = 0.5 , 0.5 max speed (and torque)
✔✔Power dissipated by resistor - ✔✔less than 0.25W
✔✔Motor maximum efficiency - ✔✔motor operate near maximum speed
✔✔Slip - ✔✔(Synchronous speed - Rotor speed) / Synchronous speed
✔✔Suitable motor based on rated power - ✔✔1.5 X output power
✔✔Gearbox efficiency - ✔✔70%
✔✔Motor efficiency at peak load - ✔✔85%
, ✔✔Baud rate - ✔✔f x no. of bit x 2
✔✔Torque motor with gearbox - ✔✔T = max dynamic load / gear ratio
✔✔Commutator - ✔✔create a continuous movement or toque, the angle between the
field and the armature must be kept constant and as close to the angle that maximise
the force moment arm as possible
✔✔PMDC uses - ✔✔light/medium duty electric drive, servos
✔✔BLDC uses - ✔✔computer hard drive, CD/DVD players, PC cooling fan, direct drive
turn table, electric vehicle
✔✔Field wound DC motor uses - ✔✔power tools, washing machine, dryer, vacuum
cleaner, fan, food processors
✔✔Stepper motor - ✔✔hold position with stop ( full torque at standstill),
✔✔DC motor drives - ✔✔high power from supply - POWER GATE (PWM input
generate by controller) - high power to motor
✔✔AC motor drives - ✔✔high power from AC supply - RECTIFIER CIRCUIT - high
power DC - INVERTER CIRCUIT (LINE FREQUENCY GENERATOR - speed input) -
high power AC to motor
✔✔Step motor drives - ✔✔high power DC supply - POWER GATE (INDEXER - control
signals [square wave] and direction) - high power to motor
✔✔Aliasing - ✔✔misrepresentation of frequencies in the analogue signal, this occur
when the sample rate is less than twice the highest frequency for the analogue signal
✔✔ZnC battery - ✔✔dry cell, 1.5V, toy battery, cheap, various shape and size, energy
density low, power service temperature, poor leakage reistance
✔✔NiCad battery - ✔✔2 way radio, video camera, power tool, relatively low energy
density, long life, high discharge rate, cheap
✔✔NiMH battery - ✔✔high energy density, reduced cycle life, no toxic metal, phone,
laptop
✔✔Li-ion battery - ✔✔high energy density, light weight, fragile, protection circuit
required, notebook, mobile phone
SOLUTIONS RATED A+
✔✔Integrator amplifier - ✔✔G = -1/(jwCR) = -Zf/Z1 = -Vout/Vin
Vout = 1/(RC) x intergrate V dt
✔✔Low-pass filter - ✔✔G = -(R/R1) x 1/(1+ jw/w0)
✔✔S-R latch - ✔✔have memory of the last button pressed
✔✔Single-shot delay timer - ✔✔Change value of their output after a certain period of
time has elapsed since the timer was enabled
✔✔Coulomb (electromagnet) - ✔✔F = kq1q1/(r^2)
✔✔Faraday law - ✔✔the magnetic flux flowing through a closed surface is equal to the
integral over the whole surface of the scalar product of the field gradient and the normal
to an infinitesimal surface element
✔✔Lorentz - ✔✔F = qE + qv x B
✔✔PMDC - ✔✔F = ilB
T = 2ilBa = ki
Vb = 2alBw = kw
✔✔Stall torque - ✔✔No speed torque
✔✔Armature resistance - ✔✔i^2 R
✔✔Motor Power, P - ✔✔P = torque x w = iVb
✔✔Motor peak power - ✔✔efficiency = 0.5 , 0.5 max speed (and torque)
✔✔Power dissipated by resistor - ✔✔less than 0.25W
✔✔Motor maximum efficiency - ✔✔motor operate near maximum speed
✔✔Slip - ✔✔(Synchronous speed - Rotor speed) / Synchronous speed
✔✔Suitable motor based on rated power - ✔✔1.5 X output power
✔✔Gearbox efficiency - ✔✔70%
✔✔Motor efficiency at peak load - ✔✔85%
, ✔✔Baud rate - ✔✔f x no. of bit x 2
✔✔Torque motor with gearbox - ✔✔T = max dynamic load / gear ratio
✔✔Commutator - ✔✔create a continuous movement or toque, the angle between the
field and the armature must be kept constant and as close to the angle that maximise
the force moment arm as possible
✔✔PMDC uses - ✔✔light/medium duty electric drive, servos
✔✔BLDC uses - ✔✔computer hard drive, CD/DVD players, PC cooling fan, direct drive
turn table, electric vehicle
✔✔Field wound DC motor uses - ✔✔power tools, washing machine, dryer, vacuum
cleaner, fan, food processors
✔✔Stepper motor - ✔✔hold position with stop ( full torque at standstill),
✔✔DC motor drives - ✔✔high power from supply - POWER GATE (PWM input
generate by controller) - high power to motor
✔✔AC motor drives - ✔✔high power from AC supply - RECTIFIER CIRCUIT - high
power DC - INVERTER CIRCUIT (LINE FREQUENCY GENERATOR - speed input) -
high power AC to motor
✔✔Step motor drives - ✔✔high power DC supply - POWER GATE (INDEXER - control
signals [square wave] and direction) - high power to motor
✔✔Aliasing - ✔✔misrepresentation of frequencies in the analogue signal, this occur
when the sample rate is less than twice the highest frequency for the analogue signal
✔✔ZnC battery - ✔✔dry cell, 1.5V, toy battery, cheap, various shape and size, energy
density low, power service temperature, poor leakage reistance
✔✔NiCad battery - ✔✔2 way radio, video camera, power tool, relatively low energy
density, long life, high discharge rate, cheap
✔✔NiMH battery - ✔✔high energy density, reduced cycle life, no toxic metal, phone,
laptop
✔✔Li-ion battery - ✔✔high energy density, light weight, fragile, protection circuit
required, notebook, mobile phone
