What is AC current

Name: What is AC current
Start: 2026-05-01T12:30:00+05:30
Location: D. K. Bardhan – Kolkata

Schedule

Fri, 01 May, 2026 at 12:30 pm

UTC+05:30

Location

D. K. Bardhan – Kolkata | Kolkata, WB

What is "Oscillation". In short the to & from movement of the pendulum of a clock is called oscillation. i.e any object starts from pt no 1 & travels to pt. no. 2 and again moves back to pt. no. 1 is called 1 oscillation. The nos of oscillations per second in called frequency and measured in terms of hertz. This frequency plays the key role in all communications. Basically this frequency is AC current. AC current is nothing but flow of electrons through any metal conductor. In metals there are free electrons which are not bound with the metal. In non metals these free electrons are not there and that is the reason why they do not conduct electricity. AC current is set at a definite frequencies. In India it is 50 cycles (oscillations)/second. In other countries this may vary. There are 2 components in the AC current ( Positive & Negative ). To make anything to travel there must be a driving force (pressure) and it is called voltage. Again there is question about quantity of electricity and it is denoted as ampere. So voltage x ampere = Watt (power). Every electrical motor is designed to operate at a definite voltage and current. AC current is the conversion of magnetic lines of force into emf (electro motive force ) or electricity. The magnetic lines of force cannot flow through any conductor. It exits the north pole and returns to south pole and complete the cycle. In generator there are 2 parts. No 1 – Stator (non moving body) & No 2 – Rotor ( rotating body on which wires are wound in definite turns) and connected to external terminals for consumption. The magnetic flux intercepts the conductor of the rotor and electricity generated. The magnetic coils are fixed at 2 or 3 pts. at certain degrees inside the stator. So when the rotor rotates inside the stator the quantity of magnetic flux is maximum when the conductors are near to the field magnets and "0" when far away from the magnetic poles. So graphically in 1 rotation of the rotor the magnetic flux is "0" voltage ( when far away from the magnetic field & then gradually builds up and is maximum when the coils are near to field magnets & then again the flux decreases & at one point it is "0". Thus 180⁰ completed. As every magnet has 2 poles (North & South). So in the next journey of the rotor (180 ⁰ of 360 ⁰) the polarity reverses. So in AC current there are 2 components ( Positive & Negative ). 1 cycle consists of – starting at "0" voltage – rising to maximum ( + ve) voltage – decreasing in ( + ) voltage & becomes "0" voltage – gradually rising to maximum (– ve) voltage & again falling in ( – ) ve voltage and then "0" voltage. This continues with every rotation of the rotor which is 50 rotations / second ie 50 Hertz/second.