modified 9 years ago

LAoE Figure 4N.5 Current Source

00:37:52

Using the BJT as a rough current source

Once VB is fixed, VE too is fixed and determines IE. But IC ≈ IE, and IE is constrained by VB.

The current source only works if VC > VE

published 9 years ago

BillyT

9 years ago

Good information, I have never thought of it that way before. You don't need to use separates power supplies, a zener diode and resistor works well. http://everycircuit.com/circuit/4742455153131520

nemethakos

9 years ago

Hi Billy, you are right, it could be used with zener reference. Actually I'm trying out the examples from the book "Learning the Art of Electronics". This circuit (the resistor are just mentioned as "load") is on page 156.

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