Vertical Lifting Security Gate Power Source  -  The circuit that I came up with is shown below.  It uses 5 identical circuits.  Each one is wired in parallel with it assigned 650F super capacitor.  A LM385 provides a 1.2v voltage reference.  A resistor divider measures the voltage across the capacitor and feeds the voltage to a low power, low voltage op amp. The output of the op amp drives an n-channel FET.  I designed the circuit for a maximum charge current of 600ma.  This would allow the use of a 10 watt solar panel, if needed, in the future.  Each of the five circuits forms a shunt type voltage regulator, limiting the voltage across each capacitor to about 2.6v.   . . . [Circuit by David A. Johnson P.E.,  11/01/09]