Quoting Tamas Rudnai : > Hi, > > I was thinking about regulating the Vdd using an amplified diode circuit. > Basically the input voltage could be varied between 4-7.2V and I am going to > set this circuit to 3.3V. The load is around 1-2mA. I was wondering if there > is any con about this? > > Thanks, > Tamas As Mike says, you can use a "Vbe multiplier" circuit (2 resistors and a BJT) as shunt regulator. Cons include poor temperature coefficient (-0.3%/K) poor initial voltage accuracy and poor line/load regulation, plus it will waste power since you will probably have to give it 3mA or so regardless of the load. A couple of red LEDs in series might work out better if you want to do that sort of thing, or just put a proper regulator in there. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" s...@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist