Electricity Flashcards
Define electric field strength
Force experienced per unit positive charge at a point in space.
Define electric potential energy.
Work done per unit charge in bringing a positive charge from infinity to that point.
Define capacitance.
The amount of charge a capacitor can store per unit potential difference.
How do LDRs work?
Resistance decreases when exposed to light intensity.
How do thermistors work?
Resistance decreases with increasing temperature.
How do piezoelectric transducers work?
Mechanical forces change the shape of the crystals (usually quartz) and an electric field is created.
How do strain gauges work?
Resistance varies with an applied force.
Tension causes resistance increase
Compression causes resistance decrease
Define gain in an op amp
How much greater the magnitude of output voltage is compared to input voltage.
Define impedance in an op amp
Resistance to the flow of current
Define inverting and non inverting op amps
Inverting: output is 180° out of phase with input
Non-inverting: output is in phase with input
Define power rails for op amps
V+/V- supply
Define open and close loop op amps
Open loop: no feedback is fed from input to output
Closed loop: feedback is fed from output to input
Define bandwidth in an op amp
The difference between the frequency limits of the amplifier
Define saturation in an op amp
Amplifier’s output is dependent on the voltage supplied.
What are the 6 properties of an ideal op amp?
Voltage gain = Vout / Vin
Infinite input impedance
Zero output resistance
Infinite bandwidth
Infinite slew rate
Zero noise contribution
