What happens if choke and starter of a fluorescent lamp are removed?

The choke is in series with the electric path (together with the starter switch) as below image : if you remove the choke the circuit will not complete to operate. If you remove the c hoke AND complete the circuit, the tube will be destroyed by excessive current. Just to clarify.

What is the voltage developed at the time of starting in a fluorescent lamp?

Fluorescent starter: Fluorescent starters are a timed switch and it provides ignition voltage to the fluorescent lamp. The ignition voltage is as high as 1000 V to initiate a discharge in the argon gas lying between electrodes.

Why is the power factor of the fluorescent tube circuit so poor?

Current in a fluorescent lamp is limited mainly by a choke in series with it, which is major chunk of impedance. The power factor therefore is very low at about 0.5. A capacitor is usually connected across its supply terminals to compensate for the same, and improve the power factor to above 0.9.

What is in a fluorescent tube?

A fluorescent lamp consists of a glass tube filled with a mixture of argon and mercury vapour. Metal electrodes at each end are coated with an alkaline earth oxide that gives off electrons easily. When current flows through the gas between the electrodes, the gas is ionized and emits ultraviolet radiation.

How much voltage is produced by choke in fluorescent tube light?

Then the voltage in the tube drops (typicaly to about 100 V), the current keeps the electrodes hot and, because the ionized gas has a negative resistance, the impedance of the choke limits the current.

Why choke of fluorescent tube is called as ballast?

The choke supports the rest of the supply voltage. The ‘choke’ or magnetic ‘ballast’ is a coil with a magnetic core (using silicon steel) that performs three functions. The fluorescent lamp has two electrodes at its two ends but the voltage needed for breakdown is very high, much higher than the supply voltage.

What is the difference between choke and ballast?

A choke is an inductor designed to have a high reactance to a particular frequency when used in a signal-carrying circuit. An electrical ballast (sometimes called control gear) is a device intended to limit the amount of current flowing in an electric circuit.

How do fluro lights work?

Fluorescent lamps work by ionizing mercury vapor in a glass tube. This causes electrons in the gas to emit photons at UV frequencies. The UV light is converted into standard visible light using a phosphor coating on the inside of the tube.

How can the power factor of a fluorescent tube be improved?

The objective of the work is to improve the power factor of the compact fluorescent lamps (CFLs) by reducing the Total Harmonic Distortion (THD). The power factor is improved by using modified electronic ballast with passive valley-fill power factor correction circuit.

Why do fluorescent lights need a capacitor?

Fluorescent lamps form an inductive load on the AC mains supply. As a result large installations of such lamps suffer a poor power factor and resultant voltage drop. Adding a capacitor to each lamp corrects the power factor bringing it back close to unity (1.0).

What is the cut-off voltage of a diode?

The diode is considered cut-off (or off) when the forward voltage falls below the threshold voltage. Therefore, the cut-off voltage would be considered to be a forward voltage less than the threshold voltage. Unfortunately, you are mixing terms from the relay world, into the semi-conductor world.

What is pick up and drop out voltage?

One common electrical characteristic that is specified of Relays is the pick up and drop out voltage. These values are defined as follows: Pick up voltage (also defined as pull in voltage, or must operate voltage): As the voltage of a de-energized Relay is increased, this is the value at or below which all contacts must function.

What is knee voltage and cut off voltage?

This is called the knee voltage or cut-in voltage and is equal to the barrier potential of the p-n junction. The cut-off voltage is the voltage at which a battery is considered fully discharged, beyond which further discharge could cause harm.

What is the difference between threshold voltage and cut off voltage?

The threshold voltage is also referred to as the turn-on voltage or cut-in voltage. The diode is considered cut-off (or off) when the forward voltage falls below the threshold voltage. Therefore, the cut-off voltage would be considered to be a forward voltage less than the threshold voltage.