What types of ballasts are there?

There are three main categories of ballast for fluorescent and discharge lamps. Conventional ballasts (CCG) are magnetic chokes operating at 50 Hz mains frequency; they require a separate starter and have self-losses of 10–20 % of lamp wattage. Low-loss ballasts (VVG) use improved core materials to reduce losses slightly but still need a starter. Electronic ballasts (EVG) operate at 25–50 kHz, combine ballast and ignition in one unit, eliminate the starter, and save around 23 % energy versus a CCG. For LED modules, a dedicated LED driver – either constant-current or constant-voltage – replaces the ballast.

When do you need a ballast?

A ballast is required whenever you operate a gas-discharge lamp – including all fluorescent tubes (T5, T8), compact fluorescent lamps without an integrated driver, metal halide (HQI) lamps and high-pressure sodium lamps. Without a ballast, the discharge current in these lamps rises uncontrollably after ignition, destroying the lamp within seconds. LED modules that are not self-contained retrofit lamps also need a dedicated LED driver. Standard incandescent and halogen lamps (GU10, E27, etc.) connect directly to mains voltage and do not require a ballast.

Can you simply replace a fluorescent tube with an LED tube?

Replacing a fluorescent tube with an LED tube is possible, but the approach depends on the LED tube type. Ballast-compatible LED tubes are designed to work with a specific EVG – check the compatibility list supplied by the LED tube manufacturer. Mains-direct LED tubes require the existing ballast to be disconnected or bypassed, and the luminaire rewired so that live and neutral connect directly to the lamp holders. In both cases, any starter in the circuit must be replaced with a starter-bridge adapter. Always isolate the luminaire from the mains before starting work.

What is the difference between a transformer and a ballast?

A transformer (or halogen transformer) steps 230 V AC down to 12 V AC or DC for low-voltage halogen lamps such as GU5.3 / MR16 types. It changes voltage but does not limit current in the way a ballast does. A ballast is connected in series with a gas-discharge lamp specifically to limit the discharge current and, where necessary, deliver an ignition voltage pulse. An LED driver is neither a traditional transformer nor a ballast – it rectifies mains AC and delivers a precisely regulated DC output (constant current or constant voltage) to power LED modules safely.

What is the difference between CCG, VVG and EVG?

All three are ballast types for fluorescent lamps, differing in technology and efficiency. A CCG (conventional ballast) is a simple magnetic choke with losses of 10–20 % of lamp wattage; it needs a separate starter and has been banned for new sales in the EU since 2005. A VVG (low-loss ballast) uses better core materials to reduce losses modestly but is also being phased out under EU ecodesign rules. An EVG (electronic ballast) operates at high frequency (25–50 kHz), integrates the ignition circuit, eliminates the starter, reduces system power by roughly 23 % and enables flicker-free dimming. Only EVGs with EEI class A1 or A2 may currently be sold in the EU.

Do LEDs need a ballast or a driver?

LED lamps and modules do not use a ballast in the traditional sense, but they do require a LED driver to operate safely. The driver rectifies mains AC and delivers a regulated DC output – either a fixed current (e.g. 350 mA or 700 mA for constant-current drivers) or a fixed voltage (12 V or 24 V for constant-voltage drivers). Self-contained LED retrofit lamps (E27, GU10, etc.) have the driver integrated into the lamp base and connect directly to mains voltage. LED modules used in professional luminaires and LED strips always require an external driver matched to the module's power and current specification.

How do I connect a ballast?

A ballast is wired in series between the mains supply and the lamp. For a CCG or VVG fluorescent circuit: connect live to the ballast input, the ballast output to one lamp pin, the starter in parallel with the lamp, and neutral to the other lamp pin. For an EVG: connect live and neutral to the EVG input terminals; the EVG output connects directly to the lamp holders – no starter is used, so fit a starter-bridge in the starter socket or remove the starter loop. For HID lamps, wire the ignitor in series between the ballast output and the lamp. Always isolate the circuit from the mains before working on the wiring, and consult a qualified electrician if in doubt.

How can I test a fluorescent ballast?

The quickest way to identify and test a fluorescent ballast is visual inspection. If a separate starter is present in the luminaire, the ballast is a conventional CCG or VVG. If there is no starter socket, the ballast is an EVG. To check whether the ballast is functioning: replace the starter with a known-good unit (for CCG/VVG) or substitute a known-good lamp (for EVG). If the lamp still fails to start, measure the ballast output voltage with a multimeter – a CCG should show mains voltage across its output terminals; an EVG should show a high-frequency voltage. A ballast showing no output voltage is faulty and should be replaced.

Ballasts

OSRAM OPTOTRONIC® Phase-cut OTE 25/220…240/700 PC

Compact constant current LED drivers. Product features: Dimmable via leading edge/trailing edge • : Compact housing for mounting in very tight spaces • Compatible with many common...