The function of choke is to provide high voltage enough for
ionization to take place in a tube light and after
establishment and substenance of ionization, limit the
voltage across the tube. That is the reason why a tube
fuses when the choke is shorted.
At the time of starting a tube choke gives rise to high
voltage by di/dt nearly 1000 volts by starter ON-OFF
function rate of change of voltage becomes high due to
inductance of choke. This high voltage starts ionization of
gas in the tube. Once gas gets ionised and starts
conducting then starter gets out of circuit and circuit is
completed only through choke which now share voltage(limit
voltage) for tube because after esabilishing ionization now
to maintain it only nearly half of the voltage is required.
choke is highly inductive , so it opposes any sudden change
of voltage .
At start it stores electrical voltage and passes it with
high amplitude within sec(1000-1200V) for ionisation of
gases in tube bar .
the property of the inductor is to oppose the rate of
change of current through it suddenly. At the time of
starting it requires high voltage to ionise the gas (
through creating potential difference between the
electrodes) in the tube so choke creates required potential.
The starter is same as that of a capacitor, to improve the
power factor the total system(connection of R and L) it is
To prevent the mal operation of a differentially connected
relay while energizing a transformer, the relay restraining
coil is baised with
(a)second harmonic current
(b)fifth harmonic current
(c)third harmonic current
(d)seventh harmonic current