The circuit is powered by a 9V battery, with a 5V regulator for the PICAXE 14M to set the scale of its ADCs. The clock provides a 1-second pulse to establish the charge measurement interval. The two ADC inputs measure voltage and current. Another input notifies current range to the program. The clock motor requires that alternate pulses be of opposite polarity. The resistors in series with the coil compensate for the greater voltage; the clock runs on 1.5V. It was found that a pulse width of 18 ms causes the clock to run backwards, 25 ms clockwise. The green LED is just for visual feedback. It flashes for each coil pulse, or if an input is over 5V. When used with the optional AC Current sensor a jumper provides offset for the 4 MA base current of the sensor.