Learn Hardcore Dutch: Het lampje gaat uit als de batterij leeg is. - The little light turns off when the battery is empty.

The suffix -je forms a diminutive in Dutch, meaning “little” or showing affection. So lampje is “little lamp,” often an indicator LED. All diminutives take the article het regardless of the base noun’s gender: de lamp → het lampje. The plural is lampjes.

Why is it het lampje but de batterij?

Because lampje is a diminutive and diminutives always use het. Batterij is a common-gender noun and uses de: de batterij (plural: de batterijen). You have to memorize the gender of non-diminutive nouns like batterij.

How does gaat uit work? Is uitgaan a separable verb?

Yes. Uitgaan is separable, so in a main clause it splits: Het lampje gaat uit. In a subordinate clause the parts join at the end: … dat het lampje uitgaat. Use uitzetten or uitdoen when someone actively turns something off: Ik zet/doe het lampje uit (transitive).

Why is the verb is at the end of als de batterij leeg is?

In Dutch subordinate clauses, the finite verb goes to the end. De batterij is leeg (main clause) becomes als de batterij leeg is (subordinate clause). This verb-final rule is standard after subordinating conjunctions like als, omdat, dat, etc.

Can I start the sentence with the als-clause? What changes to word order and punctuation?

Yes: Als de batterij leeg is, gaat het lampje uit. When you front a subordinate clause, you put a comma after it and invert the subject and verb in the following main clause: gaat het lampje uit (not het lampje gaat uit).

Why is there no comma before als in the original?

When a subordinate clause comes after the main clause, Dutch normally does not use a comma before it (so no comma before als here). If you put the subordinate clause first, you do use a comma after it.

Does als here mean “if” or “when”? How is it different from wanneer and toen?

Here als can mean “when” in the sense of “whenever,” and it can also be understood conditionally as “if”—context decides. Wanneer also means “when”; it’s common in questions and is fine in statements too, though als is more idiomatic in everyday speech for conditional/whenever meanings. Toen is only for a one-time event in the past (e.g., Toen de batterij leeg was, ging het lampje uit).

Why use leeg for a battery? Could I say op, dood, or plat?

All are heard, with nuances:

leeg = empty; neutral and standard for batteries.
op = used up/out of charge; very common in speech.
dood = dead; also common.
plat = flat; chiefly Belgian/Dutch-Flemish usage.
So De batterij is leeg/op/dood/plat are all understandable; leeg is the safest neutral choice.

Can I say als de batterij leeg wordt/raakt or als de batterij leeg gaat?

You can say als de batterij leeg wordt or als de batterij leeg raakt to emphasize the process of becoming empty. You would not say leeg gaat; that’s unidiomatic. For “drains,” you can also say de batterij loopt leeg.

Why use the definite article de with batterij? Could I say een batterij or omit it?

Dutch generally requires an article with singular count nouns. De batterij implies the specific battery in the device, which fits this sentence. Een batterij would mean “a battery (any one),” which changes the meaning, and omitting the article is ungrammatical in standard Dutch.

How do I negate this sentence correctly?

To negate the light turning off: Het lampje gaat niet uit als de batterij leeg is. (niet comes before the separable particle uit.)
To negate the battery’s state: Het lampje gaat uit als de batterij niet leeg is. (This changes the meaning: it now turns off when the battery is not empty.)
Positioning niet changes what you negate, so be careful.

How do I pronounce the tricky parts?

g in gaat: a guttural sound (like the ch in Scottish “loch”).
aa in gaat: long open “a” (like “father”).
ui in uit: a Dutch-only diphthong; approximate it by starting with “uh” and gliding toward “ee.”
ij in batterij: roughly like English “eye.”

How would this look in the plural?

De lampjes gaan uit als de batterijen leeg zijn. Note plural agreement: gaan and zijn, and lampjes/batterijen.

Is accu a better word than batterij here?

Use batterij for most consumer devices and in general statements like this. Accu typically refers to larger rechargeable batteries (car/motorbike battery) or, in some contexts, a device’s rechargeable pack, but everyday speech still prefers batterij even for phones: De batterij is leeg.