Lighting Tutorial [E-BOOK]

3.1 Important for getting started: The correct starter

Therefore a starter is connected in parallel with the lamp, usually the commonplace glow starter (Fig. 3.1), with any luck an electronic starter (Fig. 3.2). The basic wiring is given in Fig. 3.3. When applying the mains voltage a glow discharge is initiated inside the glow starter (Fig. 3.4) which heats up the bimetallic contacts and causes them to close (Fig. 3.5).

Fig. 3.3: Wiring diagram of a fluorescent lamp with magnetic ballast and glow starter

Now current flows from the mains via the ballast, the cathode filament, the starter and the second filament. This way the cathodes are pre-heated. But since the glow discharge has solely been shorted by the bimetallic contact, the bimetallic contact cools down and opens again few seconds after closing. By interrupting the current through the (relatively great) inductance of the ballast a substantial voltage surge is generated across the ends of the fluorescent lamp, starting a current flow through the tube (Fig. 3.6).

Fig. 3.4: A glow discharge heats up the bimetallic contacts…

Fig. 3.5: …the contact shorts out the glow discharge, while a current limited by the ballast is flowing through the filaments…

Fig. 3.6: …the contact cools down again, which causes it to open, and a self-induction impulse fires the lamp – hopefully!

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