Ask Electronics

3316 readers

3 users here now

For questions about component-level electronic circuits, tools and equipment.

Rules

1: Be nice.

2: Be on-topic (eg: Electronic, not electrical).

3: No commercial stuff, buying, selling or valuations.

4: Be safe.

founded 1 year ago

MODERATORS

[email protected]

Using an incandescent lamp as the "resistor" for a zener/avalanche diode regulated supply (discuss.tchncs.de)

submitted 1 year ago by [email protected] to c/[email protected]

3 comments fedilink hide all child comments

The recent post on using a lamp in series to limit potential fault currents has had me thinking about using them as above. Has anyone done this? I can see advantages, cost for one - wirewound resistors can be expensive. Visual indication of a varying load. Make it "short-circuit proof"..

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 1 points 1 year ago

Standard resistors come in many standard values and many power grades, meaning you can pick a resistor that minimizes source current for your application. Incandescent bulbs come in different rated voltages and powers, but they are far from precise or standard.

Depending on the design, shunt regulators come with short protection for free without relying on a PTC fuse (incandescent bulb or otherwise). You're absolutely correct that the positive tempco of a bulb will reduce short circuit current, but how by how much and whether it is worth it depends on the application and the properties of the bulb itself.