Schematic: http://i1244.photobucket.com/albums/gg572/amandafairchild/f87a5c04.jpg
Note: The JFET acts like a short when 0V applied to the gate and as an open if V gate is less than -3V.
Formula for Vout non-inverting Op Amp: Vout=(1+(Rf/Rs))Vin
Am understanding this circuit correctly?
When the pulse is 0V the JFET acts like a short and Rs=1Kohm resistor?
When the pulse is -5V the JFET acts like an open and Rs=47Kohm resistor?
Note: The JFET acts like a short when 0V applied to the gate and as an open if V gate is less than -3V.
Formula for Vout non-inverting Op Amp: Vout=(1+(Rf/Rs))Vin
Am understanding this circuit correctly?
When the pulse is 0V the JFET acts like a short and Rs=1Kohm resistor?
When the pulse is -5V the JFET acts like an open and Rs=47Kohm resistor?
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Yes, you have it right with one very minor quibble: when JFET acts like a short, the 1k resistor is in parallel with the 47k resistor so that Rs=979 ohms.
When the JFET is a short, the circuit has a high gain, G=103, so the output is 103mVp. Assuming that the source is a symmetric AC waveform, then the maximum output voltage is 103mV and the minimum is -103mV.
When the JFET is a short, the circuit has a high gain, G=103, so the output is 103mVp. Assuming that the source is a symmetric AC waveform, then the maximum output voltage is 103mV and the minimum is -103mV.