A test of giant electrorheological valve in DC and square wave AC fields with different frequencies

The high price and less content of current Braille displays keep most of visually impaired persons from using them. The compact arrangement of Braille dots regulated by Braille standard presents a rigid limitation to develop a full-page Braille display. Electrorheological valve gives a possibility to meet these severe demands, and its pressure drop is a key parameter to design a full-page Braille display. A giant electrorheological valve in DC field and square waveform AC field with different frequencies was investigated. It was shown that the pressure drop of valve increases with the electric field strength, and decreases with increasing frequency of square waveform AC field. The pressure drop of the giant electrorheological valve is high enough for the purpose in application of a full-page Braille display. The results also show that only square waveform AC field with low frequency can provide higher pressure drops. A forcing flow of giant electrorheological fluids in channel of valve may be a solution of solving the aggregations of nanoparticles on the electrodes.