Actuators are disposed between a lower wiring substrate and an upper wiring substrate. The system may have flexible substrates or non-flexible substrates. , a light transmission of 80-92%, and consists of 58-62% SiO2, 11. If not, the microprocessors are allowed to run in their normal mode, such as by writing a value to a configuration register associated with each microprocessor. The pulse width modulation circuit provides a constant magnitude of the test current to accommodate variations of the nominal fixed impedance or variations of the voltage of the load terminal.