2015 Flashcards
Name the value that might be found using stress and strain on the straight line portion of the two
Youngs Modulus of Elasticity
Advantage of a clutch
-allows user to connect/disconnect drive to change gears, control speed, make adjustments etc.
Disadvantage of a clutch
-can slip and use up energy
-has more parts making it complex and requiring regular maintenance which may be expensive
Describe the operation of a MOSFET
-when voltage on the gate is below threshold, there is in effect no channel, no current flow source drain
-above gate threshold voltage a channel is produced, connecting the drain and source, producing a drain current
-The greater the gate voltage, the better the device conducts, the bigger the drain current
-at saturation the MOSFET performs at its best, lowest source/drain resistance, highest drain current
Electrical/electronic engineering requires specialisms in analogue electronics, digital electronics, programming and power.
Describe three skills the engineer would require.
- calculate expected values at points in a circuit
-design logic circuits, Boolean, gates, truth tables, NAND conversion, etc
-Plan programs for a required sequence - Design power supplies
Describe operation of a comparator
It provides on/off control motors either fully on or off depending on the feedback signal. The … will be driven to the required position.
Describe the operation of a difference amplifier
It provides proportional control when the … approaches the correct position. The … movement slows down and therefore the … is able to stop at the exact position with no overshoot.
What is an advantage of proportional control?
It will take the … accurately to the correct position and stop there
Explain how pulse width modulation control may be used to vary the speed of a mechanism
-The bigger the mark is compared to the space the faster it will go
-The bigger the space is compared to the mark the slower it will go
