[sdiy] Current sink schematic/calculations help.

[Veronica Merryfield]

> When measuring Iabc between the collector of Q1 and the INV input of IC1B I'm not getting anything that matches these calculations - they're not really making sense at all and changing R values isn't giving me anything I can get my bearings from. I'm getting values from a few hundred uA to a few hundred mA.

How are you measuring Iabc exactly?

Have you tried with just a resistor load for Q1 and Iabc?