gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
090328-0945 EST
ELA:
Table II shows 100% at 44.8 kHz, and 5% at 54.1 kHz. I do not know how this fits in with Fig. 3. Seems to imply that you can not start initially at 5%.
Figure 15.1 in Dow's book shows the difference between an arc and glow discharge. Both include a negative resistance region. The fluorescent lamp is definitely working in the negative resistance region and you can not control current flow by a voltage source, but must use a current source.
Dow also discusses the cathode drop as related to different emitter materials and thermionic emission.
The International Rectifier discussion does not say much about how the circuit relates to heating the filaments in the low intensity, dimmed, mode.
Obviously from the IR discussion, before breakdown, the current from the series resonant circuit of C and L passes thru the two filaments since Rlamp is very high. Once breakdown occurs C is largely shunted. But as current is reduced to the lamp more current flows thru C and the circuit Q rises because of lower losses and more current is flowing thru all of the two filaments.
This is a very ingenious circuit.
.
ELA:
Table II shows 100% at 44.8 kHz, and 5% at 54.1 kHz. I do not know how this fits in with Fig. 3. Seems to imply that you can not start initially at 5%.
Figure 15.1 in Dow's book shows the difference between an arc and glow discharge. Both include a negative resistance region. The fluorescent lamp is definitely working in the negative resistance region and you can not control current flow by a voltage source, but must use a current source.
Dow also discusses the cathode drop as related to different emitter materials and thermionic emission.
The International Rectifier discussion does not say much about how the circuit relates to heating the filaments in the low intensity, dimmed, mode.
Obviously from the IR discussion, before breakdown, the current from the series resonant circuit of C and L passes thru the two filaments since Rlamp is very high. Once breakdown occurs C is largely shunted. But as current is reduced to the lamp more current flows thru C and the circuit Q rises because of lower losses and more current is flowing thru all of the two filaments.
This is a very ingenious circuit.
.