J
James Sweet
- Jan 1, 1970
- 0
For entertainment/educational purposes I'm reverse engineering a cheap
fluorescent nightlight that died and I found it uses an arrangement of
diodes and resistors in the input that I'm unfamiliar with. Excuse the
poor ASCII schematic, hopefully the formatting holds up. The combination
of D1 and R1 is in parallel with D2 and R2, of equal value wired such
that current flowing in either direction will pass through one diode and
one resistor. Why have the diodes there in the first place instead of
just one resistor?
---------------------------------------------------------
Rest of circuit
D1 R1
Mains -------|<-------/\/\--------------------
| |
| |
------------------------->|-------/\/\---------
D2 R2
The nightlight uses a very simple capacitor ballast to limit tube
current, and the thing failed very quickly, it didn't even last 3
months. I suspect the poor photocontrol causing it to flicker near dusk
killed it but the whole thing is not very well made.
fluorescent nightlight that died and I found it uses an arrangement of
diodes and resistors in the input that I'm unfamiliar with. Excuse the
poor ASCII schematic, hopefully the formatting holds up. The combination
of D1 and R1 is in parallel with D2 and R2, of equal value wired such
that current flowing in either direction will pass through one diode and
one resistor. Why have the diodes there in the first place instead of
just one resistor?
---------------------------------------------------------
Rest of circuit
D1 R1
Mains -------|<-------/\/\--------------------
| |
| |
------------------------->|-------/\/\---------
D2 R2
The nightlight uses a very simple capacitor ballast to limit tube
current, and the thing failed very quickly, it didn't even last 3
months. I suspect the poor photocontrol causing it to flicker near dusk
killed it but the whole thing is not very well made.