Electronic rheostat method and apparatus
USRE35428E · kind E · reissue
Assignee
Inventor
Key dates
| Filing date | Jun 19, 1992 |
| Grant date | Jan 21, 1997 |
| Priority date | — |
| Expiry date | Jun 19, 2012 |
Classification
- Technology area (CPC —)General
Abstract
An electronic reostat circuit having a pulse width modulated output for controlling energization of resistive device .[.such as a vehicle dashboard illumination lamp.].. .[.A.]. .Iadd.According to one aspect of the invention a .Iaddend.comparator circuit compares a reference signal adjusted by a user with an alternating signal, preferably a saw tooth waveform, and generates a pulse width modulated output whose duty cycle varies directly with the size of the reference signal. .Iadd.According to another aspect of the invention, .[.The.]. .Iadd.the .Iaddend.reference signal is generated by a tapped resistor array wherein contacts on the array are coupled to ground by a rotary switch contact which can be adjusted by the user. By raising and lowering the reference signal, the duty cycle can be changed from a minimum to maximum and thereby produce a minimum and maximum lamp illumination signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.