fluorescent nightlight schematic

I drew up the schematic for the nightlight I asked about the other day.
http://picasaweb.google.com/lh/photo/u0r7dtGPZW8M0-BCmv9bMg?feat=directlink
FL1 is a conventional looking 4" T5 hot cathode fluorescent tube sans end caps. F1 is a 125c thermal fuse which along with diacs D5 and D6 is globbed together with a blob of thermal grease. Everything needed for it to light is in the upper section, the lower section consisting of the bridge and everything beyond is just the photocontrol. The function of most of the circuit is fairly obvious but I'm still not positive what purpose D6, D7, R1, and R2 serve.
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From what I can see, I'd say it's either for a line noise filter, or it's used to stabilize the AC ripple in order to reduce the florescent lamp flicker.
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I am happy to see a diagram like this because of my curiosity. It would be useful to know the time sequence of SW1 activation. Before our modern age, say 30 years or so ago, many lamps of this size used manual starting. Is that the case for SW1? Or is SW1 part of some kind of a relay?
It is pretty clear to me that D5 and D6 substitute for the glow starter used in pre solid state fluorescent fixtures. They break down when there is no discharge through FL1. Once the lamp conducts, the voltage across D5 and D6 is insufficient to break the diacs down and energize the filaments. C1 is not a ballast because its reactance is too high. R11 is probably the main ballast limiter. R1 and R2 are small compared to R11 so they do not limit the current.
Bill
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The switch looks to be enabling or bypassing a circuit which automatically switches the light on when it gets dark, and is nothing to do with starting the tube, as far as I can see.
The two diacs are effectively replacing a glow starter, and will pre-heat the filaments when the tube voltage is above the diac's breakdown voltage (i.e. no arc in tube yet). The thermal fuse will blow if the tube takes too long to start (and is thus assumed dead), and will disable any further attempts at filament pre-heating after end-of-life.
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Andrew Gabriel
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SW1 is a SPDT On-Off-On switch wired to select On-Off-Automatic. In the On position, the photocontrol is bypassed and the lamp is always on. Off is the center position with nothing connected, and Auto allows the photocontrol circuit to control the light. Starting is always automatic, as you say, the two diacs act like the glowbottle starter in old preheat fluorescents. Those manual start switches always made me wonder, they can't possibly be cheaper than a glowbottle.
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