Smaller or configurable transformers?

[Soul-Burn]

Transformers are used to isolate circuits, and limiting their supply to 1kW or 4kW depending on transformer type.

Sometimes, there's a good reason to isolate a circuit (e.g. requires large energy spikes), but used rarely enough that it could survive on just a battery and a trickle of power.

However, this isolation requires either a transformer, which might pull a lot of power from the source circuit, or a mechanism like a 2-battery flipper¹.

It would be useful if we could throttle down transformers, like we can with liquid/gas valves, to cap their max flow to a controlled value. That way, we could, for example, use a small wire to slowly charge batteries on remote outposts or rarely used buildings that require much power like boomboxes.

This kind of usage already exists internally for buildings such as tube access points (charges at 960W but uses spikes of 10kJ). It would let us extend the batteries for them without requiring big wires all the way there.

¹ Footnote about flippers. In addition to behaving like a big transformer, they utilize the surprising feature that batteries aren't considered consumers for overload calculations, while transformers do.