Coin examination apparatus employing an RL relaxation oscillator
US4416365A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 21, 1981 |
| Grant date | Nov 22, 1983 |
| Priority date | — |
| Expiry date | Aug 21, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D5/02
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An apparatus for coin testing including an improved inductive sensing arrangement. A coin to be tested is passed through an electromagnetic field produced by an inductor which is part of a resistor-inductor type relaxation oscillator operating at a frequency in the range of approximately 100 kHz to 1 MHz. The resulting shift in frequency of the relaxation oscillator forms the basis for testing the coin. The resistor-inductor relaxation oscillator has a linear frequency response with respect to changes in the effective inductance in the oscillator over a range of inductance suitable for testing coins and produces an output signal which is digital in nature and requires no amplitude discrimination or shaping to be suitable for counting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.