Trapping of a 100 nm bead in the hardware-feedback ABEL trap. a) Image of a trapped bead obtained by averaging 11 video frames (corresponding to 1 s of data). b) Histogram of voltages applied along the x-axis to keep the bead trapped. c) Impulse response function of the feedback electronics. The latency is dominated by the cruddy SR844 lock-in amplifier. d) Power spectrum of the voltage oscillations (blue), and fits based on Eq. 5 including the effect of measurement noise (red), and without measurement noise (black).