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.