SERIES CIRCUIT CALCULATIONS

SERIES CIRCUIT CALCULATIONS



If, for example, two or more lamps (resistances R1 and R2, etc.) are connected in a circuit as follows, there is only one route that the current can take. This type of connection is called a series connection. The value of current I is always the same at any point in a series circuit.

The combined resistance RO in this circuit is equal to the sum of individual resistance R1 and R2. In other words: The total resistance(RO) is equal to the sum of all resistances (R1 + R2 + R3 + .......)

Therefore, the strength of current (I) flowing in the circuit can be found as follows:

Electrical Fuse

Electrical Fuse



A fuse is used for protecting electrical devices and components from over currents and short circuits. A electrical fuse works by interrupting the flow of current through the melting of an internal element.

General specifications
Listed below are common specifications that apply to electric fuses are:

* Fuse types: These include:
o Miniature: These fuses are available in dimensions of 5x20mm and 6.3x32mm.

o Subminiature or micro: Also known as micro fuses, these have very small dimensions (no principal dimension greater than 10 mm) and aresuitable for compact circuit board layouts.

o Midget: These refer to fuses that have 13/32" diameter.

o Automotive: These fuses are only used in automotive.

o Blade type: These fuses are typically used in low voltage, high current applications.

o PC board: These fuses are specifically used on PC boards.

o Protective: These fuses are used for protecting secondary circuits or low voltage ICs.

* Mounting: These include:
o Solderable or surface mount
o Solderable with leads
o Replaceable with holder or clips

o Performance Ratings
There are certain performance criteria that one must consider while selecting fuses. These are:
+ Voltage rating: It is the maximum voltage, up to which a safe fault current interruption will occur.

+ Current rating: It is the maximum continuous operating current of the circuit.

+ Rated breaking capacity: It is the short circuit current at which the fuse can blow without being destructed.

+ Interrupt rating: These can be high interrupt, medium interrupt, or low interrupt.

o Performance Characteristics
There are certain performance characteristics that one must consider while selecting fuses. These are:
+ Fast acting: These fuses are used in circuits that have inrush currents or where the over current must be quickly interrupted.

+ Time lag: These fuses are used in circuits where high starting inrush currents occur and decay gradually.
Operating temperature of fuse is another environmental parameter that must be considered.

* Material of construction: These include:
o Ceramic
o Sand