[sdiy] Transistor I to V converter with gain

[Justin Owen]

Hello,

I've recently been spending some time with transistor circuits. For practice I've been trying to convert op-amp building blocks to their basic transistor equivalents.

This one has me a bit stumped: http://www.sdiy.org/juz/ItoV_converters_01.pdf

The op-amp version of this takes in an AC waveform from a 4x transistor differential amp. I'm measuring about 50uA AC to the I to V input. For an op amp, converting that to 10V PP is a matter of a resistor in the feedback loop and a little DC biasing. Getting it to work with transistors has been trickier.

Ideally, I'd like:

1) 10V PP at the output
2) Inverted
3) Attenuation of the input signal is based around 0V (i.e. it attenuates 'inward' not up or down)
4) DC-coupled
5) Uses 2x NPN or 2x PNP trannies

Not asking for much huh! I have one config with 1x NPN and 1x PNP that ticks points 1,2,3 and 4 but not 5. With the schematic listed above I have points 2, 3, 4 and 5 - but not 1 (plus the waveform on this one is a bit cleaner).

There has to be a way of getting more gain out of this circuit... I'd appreciate any help working out what it was.

Thanks!