LED current limiter ckt

[up1950s]

Found and ordered this from the eBay HO list . No CCV value needed , or have when DC only ckt is how I fly . I will let you know how it worked out . Maybe put some in parrelle to test run some <5vdc locos ?

https://www.ebay.com/itm/384095267025?_trkparms=ispr%3D1&hash=item596ddca8d1:g:eKQAAOxyFjNSPzUW&amdata=enc%3AAQAGAAACkPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSQuF9OYLb3wphIAOfpJK8RsWCwunE4YM42W9uwjSL3BPy0nFlxyubIr7JY5NuSJbr39Wi1VM%252FnTVSzOM8BOAeDFzJd9I%252Bj6xj%252FxCz2u522SjOq%252BfEd%252F2ZroXOQdI0Odtkgitv%252BW%252FyUUzbAil%252FzZCPJBQ8UWN%252F2vVaF%252FvYhh7MXzJoSlCpNFsGBd9D5q4dhMpDfA3FeKigUqR6vNDJtkZ%252FViSGiDnJLPlg0smqt4luSLXZ5q6xxvsT%252F%252BtL4sjlmbItOiSlo%252FhdyLxlgKv%252BgK4DcffD0XfcbNeTwAxSsGOBZ99cFEF7SwLMdVwAXT0VqRLbDEGfsEbnK6QYOpsbGwMIjWwG9FcKkqmegRiXFPErj%252BeXGrTrH9GW%252F320riBw%252FCL6Kg8p9xztNeV9ecUNaZwviLA8jIxey%252BMjz7yKuPrDvWzuw8OeMUj2NbNNXng3FDZOgvaUtsaB%252B960R5hapoofvyqcl1p6CRyyJUNft4PVC9ZPg%252BlqEkJ7ZPAI2zx%252BnNlNtsKOx161PuOofrPYbImlvQF3OUgBOZ%252BOKICzSUDn0xsgjCLM5Ep8QkEv7vIPxizYjknZgsdCzKWvryp9SVRZ9C3iOJyqdojRPymYzeFJK5wy6NRfGcnwNRD0YssQNjXTPn7Gqrf48nxORhVDw9Fz%252FVMBJk0372I2f7D9%252B7oQUpF%252BjrvbcZGkW%252BrtY00AoB52NF19Uc418dEyni35pxIHRF9Udn7JAGMLmQ0rZi%252FuRrBEfVSF8VejT4uDTGy2wbEEQys2wu3n6%252F8EG%252BjRQBLmIxQ%252Fd6uRaxxJnq3s9DlwjvK9jmKP3BnBad%252FDrbyKFXhQ%7Campid%3APL_CLK%7Cclp%3A2334524

[peteski]

Interesting circuit. There are also constant current diodes (single 2-terminal component, smaller than this circuit). Kato uses them on their passenger light boards.
I also don't recommend the parralel LED connection shown as one of the examples.

Other than that, 20mA is rather high current for a typical white LED N scale headlight.  Most run between 1-10mA A 20 mA current will likely look like nuclear reactor glow.  Also many small SMD LEDs (sizes 0201, 0402, 0603) are rated for only 5 or 10mA.

Here is a data sheet for a constant-current diode that comes in multiple current limits.  Those should be available from electronic distributors like Digikey or Mouser.

https://www.diodes.com/assets/product-showcases/6331581.pdf

[up1950s]

Interesting circuit. There are also constant current diodes (single component, smaller than this circuit). Kato uses them on their passenger light boards).
I also dont' recommend the parralel LED connection shown as one of the examples.

Other than that, 20mA is rather high current for a typical white LED N scale headlight.  Most run between 1-10mA A 20 mA current will likely look like nuclear reactor glow.  Also many small SMD LEDs (sizes 0201, 0402, 0603) are rated for only 5 or 10mA.

They sell many values .

[mmagliaro]

That store has a ton of cool products all in one place.  I wish my German was better.

[peteski]

That store has a ton of cool products all in one place.  I wish my German was better.

When I visit their store, all the item descriptions are in English.

Also, while the categories selection (on the left is in German at the store), when you look at the individual listings, the categories listed there (also on the left) are also in English.

[mmagliaro]

It is the categories that get me.  It's possible to figure out most of the top-level ones on the left, but if you open one of those, and see, like 20 subcategories under that all in German, it gets rough. 
When I click on a specific item, I don't think I see what you are describing.  Everything on the left of it (categories) is still in German, and the whole product description detail is in German.