capacitor Flashcards
a passive electronic
component used to store energy in an
electric field.
capacitor
capacitor is a device consists of two
conductive plates separated by an
insulating material called
dielectric
how capacitor work
- when connect to power source, 1 plate gain positive charge, other plate gain negative charge.
- creates electric field in dielectric storing energy
- amount of charge depends on capacitance, voltage, and properties of dielectric
Formula of Capacitance
C = Ke(A/d)(E0)
Ke = dielectric constant
E0 = permittivity space (8.854 x 10^-12 F/m)
d = distance of plates
A = plate area
the ability of the
capacitor to store electric charge per
unit of voltage. It quantifies how much
charge a capacitor can hold at a given
voltage and is a fundamental property of
capacitors.
capacitance
formula of capacitance (charge and voltage given)
C = Q/V
uses of capacitor
- storage
- filter
- time circuit
- signal processing
type of capacitor
* small inexpensive
*used in high frequency
applications like antennas
*Used in X-ray
*Used in MRI machines
*Fixed type
*Non polarized
ceramic
Types of Capacitors
*High capacitance for
small size
*Only polarized capacitor
*Used in power supply
circuits as filter
*Aluminum and Tantalum
type
*Fixed type
- Electrolytic
Types of Capacitors
*Good for high voltage
applications
*Fixed type
*Non- polarized
- Glass Type
Types of Capacitors
*Extremely high capacitance
for energy storage
*Used in electric and hybrid
cars
*Fixed type
*polarize
- Super capacitor
Types of Capacitors
- Includes polyester (mylar),
polysterene, polypropylene,
polycarbonate, metallized
paper, Teflon, plastic , etc
*Used for timer circuits like
clocks, alarms and counters
*Fixed type
*Non-polarize
- Film Capacitors
Types of Capacitors
*Low capacitance
*Compact size
*No leads (flat terminals for
surface mounting)
*Automatic assembly (suited
for automated PCB assembly
processes)
*High frequency response
Used for consumer
electronics (smartphones,
laptops, TV)
*Used in medical devices
*Used in automotive
electronics
*Power supply modules and
regulators
*Non-polarized – ceramic
*Polarized – tantalum and
aluminum capacitors
- Surface Mounted Device
(SMD) Capacitors
Types of Capacitors
*Used in radio tuning circuits
*Non-polarized
*Variable
- Air Capacitors
Types of Capacitors
*Preset type capacitors
*Used in timer circuits
*Non-polarized
*Variable
- Trimmer Capacitors
Parameters Needed
When Buying Capacitors
Capacitance
voltage rating
Series Capacitor formula
1/ct = 1/c1+1/c2…
Parallel Capacitor formula
Ct = c1+c2..
What type of capacitor is commonly used in
smoothing applications?
Electrolytic
What type of capacitor is used for high
frequency purposes?
Ceramic
What type of capacitor is used for timing
circuits?
Film resistor
What type of circuit can you design if the supply
voltage is 90 volts and you only have 1000 uF/60
volts capacitors available?
2 capacitors in series
refers
to the process of storing
electrical energy in the
capacitor by applying a
voltage across its
terminals.
charging
when the capacitor is uncharged, the current
flowing into the capacitor is at its _______. As time
passes, the voltage across the capacitor gradually
_________, and the charging current _________
maximum, increases, decreases
time constant formula
T = RC
charging formula
Vc = Vs(1-e^-t/T)
refers to the process of releasing
the electrical energy stored in the
capacitor’s electrical field.
discharging
ways of discharging
short a resistor
self discharged
through external circuit
discharging formula
Vc = Vse^-t/T)
The foil plates of the capacitor are anodized with a DC current. This anodizing
process sets up the polarity of the plate material and determines which side of the plate
is positive and which side is negative.
aluminum electrolytic
available in both wet (foil) and dry
(solid) electrolytic types with the dry or solid tantalum being the most common. Solid
tantalum capacitors use manganese dioxide as their second terminal and are physically
smaller than the equivalent aluminum capacitors
tantalum
