Is there any way this can be done?
I was trying to use an NPN common emitter amplifier to amplify an analogue signal centred on a voltage in the 1V to 3.5V range, using 5V and Gnd as the power rails. But while the output signal, when the resistance in series with the emitter to ground capacitor is small enough, can amplify a small signal so that the positive parts go high enough to clip close to the 5V rail, the closest to outputting ground it can get is about 1.3V. When the ratio between the resistance in series with the emitter-to-gnd cap and the collector-to-5V resistance is large it also ends up drawing quite a lot of current from the signal source, so often needs a voltage follower stage placed before it to give a lower impedance source to feed in to this amplifier's base.
Is there a way to get the output voltage a lot lower? to 0.7V or even to somewhere <0.5V?
I'm trying to amplify the incoming AC signal (the exact voltage it will vary about is constant, but could be at different centre levels depending on what exact circuitry I've got before this amplification stage) up to a clipped square wave large enough to drive 74HC series logic with 5V power. 1.3V is unpleasantly close to the highest value which HC logic counts as LOW, so I want to get down to somewhere comfortably below 1V for amplifying the lowest troughs of the waveform.
Thanks