history of ac dc

Electric Generator (AC) - The electric generator converts mechanical energy into electrical energy. The two types of generators are DC and AC generators: DC Generators - A cycle dynamo and a car dynamo are examples of DC generators. They produce ..

Therefore the non-resistive of a coil to a.c. due to the varying magnetic field is called capacitive reactance Xc. Unit of Xc is also Ohm The current leads the EMF by 90 o and the phasor diagram is: For DC, Xc becomes infinite and hence, capacitance block DC flowing th..

>As the armature rotates about an axis perpendicular to the magnetic field, it keeps on changing its relative orientation with respect to the field Thus the flux keeps on changing continuously with time This change in magnetic flux induces an emf If the outer terminals of the armature are connected..

ABCD is a trapezoid with AB ‾ parallel to DC ‾ . P and Q are the midpoints of AC ‾ and BD ‾ respectively. The length of PQ is equal to __________. => 1 2 (AB+DC) or (AB+DC) or 1 2 |AB - DC| or |AB-DC|..

In the figure, m ∠ BAD = m ∠ DAC. Which of the following theorem can be used to prove that BD DC = AB AC ? => side-splitter theorem or triangle-angle-bisector theorem or SAS similarity theorem or SSS similarity theorem..

ABCD is a square with each side 2 cm long. BD ‾ and AC ‾ are extended to E and F such that EF ‾ || DC ‾ . EF = 8 cm. Find the area of CDEF. => 12 square cm or 15 square cm or 14 square cm or 16 square cm..

If O is the center of the circle, then what is the radius of the circle? => AC or AB or DC or OA..

Use parallelogram ABCD to check which one of the following is true. => AB = AD or AB = BC or AB = DC or AB = AC..

Direct Current and Alternating Current - If the current flows always in the same direction, it is called 'direct current'. Direction current is represented as DC or dc. The current derived from a cell or a battery is direct current - since it is unidirectional. The positive and ..

Question: A commutator changes the direction of current in the coil of 1. a DC motor 2. a DC motor and an AC generator 3. a DC motor and a DC generator 4. an AC generator Answer: ..