I am trying to design a Widlar current source to drive an RC circuit/IC 555 timer. I am having some trouble simulating the current source correctly. I am using LTSpice IV and I am using their 2N2907 transistor model. I have checked my calculations twice, but the Simulated Vbe is too high and the currents are all in pico amps where they should be in milliamps. Any help would be appreciated.