06-03-2017, 06:55 AM
In a maths formula proximity usually means mutliplication, so R2R3 means R2*R3. Much better to write it explicitly.
hFE (DC current gain) and hfe (small signal current gain) are highly variable between devices and vary significantly with temperature too. Any decent design doesn't rely on hFE and hfe except perhaps for them exceeding a certain minimum value. Most current cources rely on matched devices, usually integrated onto a single silicon die. Or at the very least kept at the same temperature.
hFE (DC current gain) and hfe (small signal current gain) are highly variable between devices and vary significantly with temperature too. Any decent design doesn't rely on hFE and hfe except perhaps for them exceeding a certain minimum value. Most current cources rely on matched devices, usually integrated onto a single silicon die. Or at the very least kept at the same temperature.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
