Electronics > Projects, Designs, and Technical Stuff
Fluorescent lamp ballast question
iXod:
--- Quote from: james_s on August 11, 2019, 09:40:05 pm ---That depends on where you are. When I hear "switch start" I think of the inexpensive fluorescent desk lamps that were once common, where instead of a starter the power switch is a momentary contact wired as a starter would be. To turn on the lamp you hold down the power button until the ends glow and then release it and the tube starts. To turn it off the switch interrupts the power.
--- End quote ---
That's correct.
themadhippy, see #1 under this topic:
http://www.repairfaq.org/sam/flamp.htm#fb2
Fluorescent lamp circuits are of 3 types:
- "starter" start (uses a separate starter component) automatically starts
- switch start (no separate starter) - must hold switch in a temporary "start" position
- autostart (electronic ballasts are of this type) "quick start"
themadhippy:
As mentioned above
--- Quote ---That depends on where you are.
--- End quote ---
In the land of 240v and 50Hz, florry tubes were you need to
--- Quote --- "hold switch in a temporary "start" position
--- End quote ---
are about as common as rocking horse shit. However whether they use a manual switch,or starter the ballast is the same.
iXod:
Haven’t you seen those old large workbench magnifiers on an articulated arm with a round fluorescent tube in it? Those typically have a switch-start circuit.
james_s:
--- Quote from: themadhippy link=topic=203694.msg2609667#msg2609667 ---
In the land of 240v and 50Hz, florry tubes were you need to
--- Quote --- "hold switch in a temporary "start" position
--- End quote ---
are about as common as rocking horse shit. However whether they use a manual switch,or starter the ballast is the same.
--- End quote ---
Like I said, it depends on where you are. The old manual switch start configuration was *very* common in the USA, I still have at least 3 lights of that type, one desk lamp and two handheld UV lamps, all from the 1970s. The stove in the kitchen at our cabin (also 1970s) has the same arrangement on the fluorescent light over the control panel.
For portable fluorescent lamps it was almost ubiquitous, they made many millions and millions of them, they used to be common as muck.
james_s:
--- Quote from: iXod on August 11, 2019, 07:36:54 pm ---This is actually in a small photographer’s light table, used to view transparency film.
--- End quote ---
Most of this discussion is academic at this point. Unless you want to retain the old style preheat start magnetic ballast arrangement to keep a vintage item original, just replace the ballasts with a modern multi-lamp electronic ballast. The type is not even all that critical, T12 tubes all run at about the same current (ignoring HO and VHO types which you'll rarely run into at home) and most electronic ballasts will work with a fairly wide range of lamp types. All you need is a ballast that lists F20T12 as a supported lamp type and you are good to go.
For reference, F20T12-KB decodes to Fluorescent, 20 Watts, Tubular, 12/8" (1.5") diameter, "Kitchen & Bath" which is one of the old halophosphate phosphor blends, IIRC it was a bit warmer than "Cool White", but not as warm as "Warm White". Electrically speaking, all F20T12 lamps are identical.
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