taken from http://www.techlib.com/electronics/battery_chargers.html.
The circuit is supposed to charge 6V battery (shown as Zener diode in the circuit). According to the author, this circuit can charge a battery with a higher voltage than what the cell generates. The solar cell is simulated with a 3V battery and a resistor. The circuit is here https://www.circuitlab.com/circuit/859v6932b322/solar-charger/
I can see that the transistors are on, but the zener diode does not turn on meaning that its voltage does not reach 6V.
Any idea why this is not working? Any suggestions for alternatives/changes?