Vactec vactrols vs. Smallbear's workalikes -- some observations and questions

[midwayfair]

First, I am by no means saying that there's anything wrong with the workalikes. I buy them all the time and have used them in several projects and almost every time they work great.

The LDR side in the 5C1 and 5C3 clones, by every metric I've been able to measure them, is basically identical.

I HAVE, however, noticed a kind of weird difference. It's in the LED side. Essentially, the LED in the Macron clones works just like a normal superbright LED. The forward voltage is pretty much spot on to a white LED, and it seems to draw the same amount of current.

The VTL5C1s have the biggest noticeable difference. They seem to require less current limiting to get to their brightest point. The measured forward voltage is ... higher than a green LED but lower than a blue LED, at least on the few I have left here. (I used to have dozens, but I used them all!) I got just under a 3V drop on mine.

The result is that under some circumstances, when the ON resistance is critical, just dropping in the Macron to replace the Vactec part might require an adjustment. In the circuit I was messing around with, I got a lower on resistance with the macron but higher dark resistance with the vactec under the same conditions. Extremely similar after testing three of each (so they're also very consistent).

I'm not too keen on cutting open a few $8 parts to see what's inside, but I wonder if anyone has any insight into this, or if anyone's observed something similar.

I'll be xposting this, so if I hear anything else where I'll let people know.

[smallbearelec]

...have used them in several projects and almost every time they work great.
...under some circumstances, when the ON resistance is critical, just dropping in the Macron to replace the Vactec part might require an adjustment.

Yes. Other customers have reported similar.

Regards
SD