# Make a Negated General Impedance Converter

A General Impedance Converter (GIC) looks like this:

Where

$$Z_{tot} = \frac{Z_1*Z_3*Z_5}{Z_2*Z_4}$$

But I need a circuit that gives me $$\ \frac{1}{Z_{tot}}\$$

How would I create a circuit that gives me $$\ \frac{1}{Z_{tot}}\$$ for Zin?

(Or something like $$\ Z_{in} = \frac{Z_2*Z_4}{Z_1*Z_3*Z_5}\$$)

The problem is if I put an inductor on this circuit, I can't select a series of impedance's Z_1 through Z_5 using only resistors and capacitors to end up with a combined impedance of 1.

• Hmm interesting. – Andy aka Jul 29 at 22:49
• So you want a general conductance converter (GCC?) – jonk Jul 30 at 0:23
• @VoltageSpike So you just need to insert a transconductance -- something that presents current at the output given voltage at the input. Like a BJT. ;) – jonk Jul 30 at 18:45
• @LvW I want to be able to reverse the impedance of an inductor, using only resistors and capacitors. So if I had an inductor on Zin, I could match the impedance with an inverse impedance. – Voltage Spike Jul 31 at 19:21
• ....and what is the unit for the "inverse impedance"? Is it capacitor? – LvW Aug 1 at 8:16

In theory, the inverse of the inverseconverse of the converse is the original impedance which was a filter with a bunch of RC's.

NIC Negative Impedance Converters give the negative of impedance , not the inversion. The performance as shown would be highly vulnerable with stray coupling. Yet the desired or expected performance was never specified.

• So, if I put an inductor on Vin can I get 1/Z_l from the circuit? – Voltage Spike Aug 5 at 20:37
• You have it backwards.. on the top half you put C on Vin+ then Vin appears as an inductor yet current limited... – Tony Stewart Sunnyskyguy EE75 Aug 5 at 20:44
• The input resistance at the node Vin is Z=-Z1Z3Z5/Z2Z4. Hence, there is only a sign inversion. Is that the solution the OP was asking for? – LvW Aug 6 at 7:19
• Yes @LvW Thankyou. The conversion is just the opposite polarity not an inversion. my bad choice of words. – Tony Stewart Sunnyskyguy EE75 Aug 6 at 7:28
• I rather think that the OP has made a bad choice of words resp. symbols. He did mention Zin=1/Ztot.....whatever this could mean... – LvW Aug 6 at 9:02