Circuit elements having no moving parts: for indicating devices for fluid signals

Official title: {for indicating devices for fluid signals (output arrangements in electronic computers G06F3/14; luminous advertising G09F13/00; name or number plates with interchangeable characters G09F7/00; fluid operating means for indicating or recording members in measuring instruments G01D5/42; fluid information or pulse transducers for converting variations of fluid pressure into other physical quantities F15B5/003)}

F15C1/007 (Circuit elements having no moving parts: for indicating devices for fluid signals) appears on 4 US grants and 4 published applications in this corpus.