What happen when hz is increase?

Answer 1

Your question is rather vague, but what you may be asking is, "What happens in a circuit if the supply frequency is increased?"

Well, circuits have some degree of natural resistance, inductance, and capacitance, which may be modified with resistors, inductors, and capacitors. Frequency affects each of these, as follows:

• Resistance -Resistance is inversely-proportional to a conductor's cross-sectional area. In a DC circuit, charge flow distributes itself across the full cross section of the conductor. However, with AC currents, an effect called 'skin effect' comes into play -this describes the tendency of charge carriers to move closer to the surface of the conductor, essentially reducing the effective cross-sectional area of the conductor, and increasing its resistance. We call this the 'AC resistance' of the conductor; at normal supply frequencies (50/60 Hz) this is insignificant, however it increases significantly with frequency.
• Inductance -Inductive reactance opposes the flow of AC current, and is directly proportional to the circuit's inductance and to the frequency of the supply. So, as frequency increases, the circuit's inductive reactance increases.
• Capacitance -Capacitive reactance opposes the flow of AC current, and is inversely proportional to the circuit's capacitance and to the frequency of the supply. So, as the frequency increases, the circuit's capacitive reactance falls.