Unit 1: Topic 4: Equations, Symbols and Units and Definitions

Question 1

1) Alternating current (AC):

Answer 1

Value of the current is constantly changing.

Question 2

1) Capacitance:

Answer 2

A measure of a capacitor’s ability to store charge. Measured in Farad’s.

Question 3

1) Current:

Answer 3

Amount of coulombs of charge that pass a point per second (I=Q/t).

Question 4

1) Direct current (DC):

Answer 4

Current flows in one direction only in a continual loop.

Question 5

1) Differential mode:

Answer 5

In reference to Op-amps. (Both the inverting and non-inverting inputs are used in this mode).

Question 6

1) Electric field:

Answer 6

A region where a charged particle experiences a force without being touched.

Question 7

1) Electromotive force (E.M.F):

Answer 7

The electrical energy given to each coulomb of charge as it passes through the source.

Question 8

1) Frequency:

Answer 8

The number of waves produced in one second (f=N/t).

Question 9

1) Internal resistance:

Answer 9

The resistance from within a cell or battery (only considered when a current is flowing).

Question 10

1) Inverting mode:

Answer 10

Positive input (non-inverting input) voltage is connected to 0V.

Question 11

1) Lost volts:

Answer 11

Voltage dropped across the internal resistor inside the battery.

Question 12

1) Peak voltage:

Answer 12

Greater than the r.m.s voltage. Peak value in UK is 325V (max voltage).

Question 13

1) Period:

Answer 13

Time taken for one wavelength to pass a point.

Question 14

1) Potential difference:

Answer 14

The difference of electrical potential between 2 points.

Question 15

1) Resistance:

Answer 15

A measure of the opposition to current.

Question 16

1) Root mean square voltage (Vrms):

Answer 16

Average value of voltage. The Vrms is equal to d.c voltage (230V in UK).

Question 17

1) Saturation:

Answer 17

Output voltage can not rise above or fall below the supply voltage. In the situation where Vo reaches it’s limit it is said to be saturated.

Question 18

1) Terminal potential difference (Vtpd):

Answer 18

The voltage measured across the cell (p.d across it’s terminals).

Question 19

1) Voltage:

Answer 19

Amount of energy given to each coulomb of charge (V=Ew/Q).