Halfwave single rail precision rectifier with ground referenced input

178

01:33:12

I built this circuit using a TSH 22 opamp ( quite fast 15V / uS ) and BAT 46 Schottky diodes, it worked but there was a bit of an error in that the peak of the rectified waveform was a bit higher than the peak of the input waveform ( 1 KHz sine wave ) anyone know why that might be ? 

I have added the 2K35 resistor to equalise the effect of input bias currents ( important in a precision application like this ) it has no effect  on the simulation but would in a real circuit.

published 7 years ago

eekee

7 years ago

You know you've got two different diodes here? Just checking. Did you check what values the resistors actually are in your built circuit?

gasboss775

7 years ago

The diodes were supposed to be the same, I've changed the schematic to reflect this. I actually checked my resistors with a meter just to make sure they were correct and they were. I have tried out several different rectifier circuits and they are all giving a similar error.

eekee

7 years ago

Ok. How about the 12V offset, does it push the input close to its limit? I just recently noticed some op-amps outputs snap to the nearest power rail (or even the opposite rail) when the inputs go out of bounds.

eekee

7 years ago

Huh... I attached a voltage source to drop the output by 12V to get EC to report fractions of 1V, and it started out with a 1.03V peak, but soon dropped to 999mV.

zorgrian

7 years ago

Eh?

gasboss775

7 years ago

The inputs are biased to 12 volts the power rail is + 24 V the -ve power rail is connected to ground. Take the output between the output and the 12 v reference point using a voltmeter ( in EC or for real )

eekee

7 years ago

Oh that makes sense.

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.