Capacitive transistorized signaling device
US4088904A · kind A · utility
Inventor
Key dates
| Filing date | May 10, 1976 |
| Grant date | May 9, 1978 |
| Priority date | — |
| Expiry date | May 10, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/975
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A capacitive transducer providing an output for a signal with respect to an on-off mode which depends on a signal having a step function, the signal source is fed to a transistor or suitable amplifier having its base connected to a capacitance sensing means. Resistors are provided for appropriate biasing, current limiting and drain functions as well as capacitors for capacitance balancing purposes. The capacitance sensing means can comprise a touch switch which when touched has its capacitance increased causing the device to function. The change in capacitance can be registered with respect to the rise time or the fall time of the signal, or the leading or trailing edge of the wave. The transistor or amplifier is connected to a load so that when a change of capacitance is sensed, the change will be registered. Other embodiments can incorporate differential amplification means and means to drive the active components with the voltage of the signal source or the clock voltage. The transducer element maybe incorporated into mechanical moving elements that provide an electrical analog of such movement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.