# Electronics/Scratch pad

## Parts list and theory[edit]

Voltage = potential between two charges. Defined as the derivative of the flux linkage:

Current = flow of electrons Defined as the rate of change of the charge:

There are 3 parameters in an electrical circuit:

Resistance =

In a resistor voltage and current are in sync.

In capacitors voltage leads current. Capacitors are good as a low pass filter.

In inductors current leads voltage. Current equals the negative derivative of the voltage. Inductors are good as a high pass filter.

relationship between voltage and current

in a circuit

in series voltage drops and current stays constant in parallel voltage stays constant and current divides according to the resistance

voltage stays constant in parallel and current drops in p

pizoelectric = a crystal under compression creates current

transformers

vacuum tube = electron emitter in a vacuum

integrated circuit a semiconductor doped with impurities

group 4 elements doped with group 3 and 5

electrons and holes

ground

## applications[edit]

Resistors in series (Christmas lights, stove)

computer

3.5, 5, 12 Volts

lamp

monitor

power distribution (three phase power)

radio

modem

speaker

## circuit design[edit]

bandgap

cmos

flip flop

computer parts

leakage current