- The capacitor's function is to store electricity, or electrical energy.
- The capacitor also functions as a filter, passing alternating current (AC), and blocking direct current (DC).
- This symbol -||- is used to indicate a capacitor in a circuit diagram.
Capacitors are used in circuits to store electrical charge for a short time. They can be either polarised or non-polarised, which mans either that they have to be connected the right way round (like the LED) or you can connect them anyway you like.. (like the resistor). If a capacitor is polarised it has a slightly different symbol on the circuit diagram and it is marked on the case with a plus-sign (+) or a minus sign (-)
Tantalum capacitors are used in smaller electronic devices including portable telephones, pagers, personal computers, and automotive electronics.
Tantalum capacitor SPECIFICATION:
Operating Temperature Range : -55 to + 125°C
Rated Working Voltage Range : 4 to 50 V DC
Nominal Capacitance Range : 0.1 to 1500μf
Capacitance Tolerance : ±20% ±10% (120Hz, ±20°C)
Leakage Current : Not more than 0.01CV [μA] or 0.5μA whichever is greater
Polarized Capacitor
Polarized capacitors are the electrolytic type or tantalum type.
Polarized capacitors have large leakage current if the voltage is inverted.
The tantalum capacitor is a highly reliable type of solid capacitor or electrolytic capacitor. Surface mount tantalum capacitors are increasingly being used in circuit designs because of their volumetric efficiency, basic reliability and process compatibility.Non Polarized Capacitor
There are two types of non polarized capacitors. The plastic foil that are non polarized by nature and electrolytic non polarized capacitors that are actually two capacitors in series (back to back) so that the result is non polarized with half the capacitance.
P-C has a small size with the large capacitance, is used only in DC circuits or circuits related to DC current.
non-polarized caps are typically used in low voltage situations, both AC and DC. Polarity is not critical. Measured in pico farads typically. A basic three symbol code is used on some capacitors. The first two marked digits are the first two digits of the value, and the third digit is a multiplier. This marking system is exactly the same as the marking system used for ceramic capacitors. All the values marked are in pico Farads.
Tolerance
All components differ from their marked value by some amount. Tolerance specifies the maximum allowed deviation from the specified value. Tolerances are normally expressed as a percentage of the nominal value.
For example, a component with a marked value of 100 and a tolerance of 5% could actually be any value between 5% below the marked value (95) and 5% above the marked value (105).
Decimal multiplier prefixes are in common use to simplify and shorten the notations of quantities such as component values.
Capacitance, for example, is measured in Farads, but the Farad is far too large a unit to be of practical use in most cases. For convenience, we use sub-multiples to save a lot of figures. For example, instead of writing 0.000000000001 Farads, we write 1pF (1 picofarad).
The more common prefixes and the relationships to one another are as follows.
| Abbrev. | Prefix | Multiply by | or |
| p | pico | 0.000000000001 | 10-12 |
| n | nano | 0.000000001 | 10-9 |
| µ | micro | 0.000001 | 10-6 |
| m | milli | 0.001 | 10-3 |
| - | UNIT | 1 | 100 |
| k | kilo | 1000 | 103 |
| M | mega | 1000000 | 106 |
| Units | ||
| 1000 pico units | = | 1 nano unit |
| 1000 nano units | = | 1 micro unit |
| 1000 micro units | = | 1 milli unit |
| 1000 milli units | = | 1 unit |
| 1000 units | = | 1 kilo unit |
| 1000 kilo units | = | 1 mega unit |
