We present sensors for electrical DC and RF voltage measurements employing the principle of electrostatic force. Microelectromechanical devices have been developed, fabricated and optimized, which are based on multiple parallel capacitances with a common movable electrode. By applying a voltage to one capacitance, a force is generated which is translated into mechanical motion, balanced eventually by the mechanical spring force of the suspension. Operating the device at electrical frequencies above mechanical resonance allows measuring the RMS value of the signal, supplementing conventional methods. At DC and RF voltage excitation the resolution has been enhanced to be better than 0.1%. The usable frequency range has been extended to above 10 Megahertz at RMS voltage levels of below six volts.