Microorganisms can grow on an electrode and either give or receive electricity from it. This allows making better biosensors, or driving bioproduction processes with electricity. It is poorly understood how microorganisms actually interact with the electrical control used to drive the sensor or reactor system. Here, we wish to develop novel micro-electronic control systems and algorithms able to deal with microorganisms in terms of their low current levels, the delay they show in response to stimuli, and their behaviour as parts of an electrical circuit. In the latter context, we will evaluate the behaviour as capacitor or diode by the bacteria and this way learn much about how bacteria respond to fluctuating electron donor/acceptor supply, and what the minimal potential difference (and thus energy level) is needed to sustain metabolism.