Demos by PIRA

  7A10.10UV light hits charged zinc plate and discharges electroscope.
  7A10.35Light through different filters into phototube changes current.
  7A10.40Several commercial solar cells.
  7A10.40Commercial solar cell spins propeller using small arc lamp.
  7A10.40Commercial solar cell spins propeller using halogen light source.
  7A10.43Recording modulates laser beam which hits solar cell and amplifier.