ELECTRONICCCC

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Resistance

the measuremnt of the opposition of the current using the unit of OHM

Conductance (G)

the measurement of th ability to conduct current

Resistivity

he mesurement of how good a conductor or insulator material is, which is dependent on the size and shape of the material

What affects resistance

Resistivity, length and cross sectional area

Potentiometer

A 3 terminal device connected in parallel with the input that has linear variable resistance, used to vary voltage (light dimmers and speed fan controlers)

Rheostat

A device connect in series, used to vary current

Light dependent resistors (LDR)

used to detect light levels, eg in automatic security lights. Their resistance decreases as the light intensity increases.

Thermistors

variable resistors that change accordingly to temperature

how to find the resistance of a conductor

(resistivity x length of conductor )/pi x radius

Voltage dependent resistors (VDR)

Bi directional resistor that decreases resistance when the voltage increases

loading effect

the impact a load has on a circuit (changes in voltage or current)

how to find total resistance in series circuit?

r1+r2+r3

how to find total resistance in parallel circuit?

1/r1 + 1/r2 + 1/r3

Voltage divider rule

V_r1= r1/r1+r2+r3 x voltage

how to find the total current of parallel resistive circuit

i1+i2+i3

current divider rule for 2

I_R1=R2/R1+R2 x I_T

How to find current in a single component

voltage drop / resistance

How to find voltage in a single component

current x total resistance

How to find resistance in a single component

Voltage drop / current

How to find current in a single component

Supply voltage / total resistance

How to find total supply voltage in a single component

current x total resistance

How to find total resistance in a single component

supply voltage/ current

Current is directly proportional to

total supply voltage

capacitors

A component that stores energy and acts as a short term battery and opposes changes in voltage

How the find the charge of a capacitor

Capacitance x voltage

Pico

10^-12

nano

10^-9

micro

10^-6

Temperature Coefficient

materials that experience an increase in electrical resistance when their temperature is raised

Aluminium electrolytics

capacitors that have a capacitance range from 1 micro farads to 22000 micro farads and have a common tolerance of ±20% or -10 to +50

Non-polarized electrolytes

a capacitor that has no positive terminals nor negative terminals

Tantalum electrolytes

Electrolytic capacitors that have a higher capacitance density but are usually smaller with a capacitance of 0.1 to 68 micro ferrods

how to find the total capacitors in series

1/c₁+1/c₂+1/C₃

How to find the voltage of a capacitor

Charge / capacitance

Voltage divider rule for capacitors

Total capacitor / Capacitance of the desired capacitor x total supply voltage

How to find the capacitance of capacitors in parallel

C₁+C₂

How to find the charge of capacitors in parallel

Q₁+Q₂

what affects capacitance

Permittivity of dielectric x cross sectional area of plates/ distance between the plates

How to find time constant

Inductance (henrys) / resistivity

how to find power

V x I

Dissipation

the dissipation of power that related to the resistivity of a component (more resistance = more )

dielectric

A insulator present in capacitors that separate positive and negative

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