Trailer marker light substitution circuit
US4380718A · kind A · utility
14Cited by
4References
7Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | May 22, 1981 |
| Grant date | Apr 19, 1983 |
| Priority date | — |
| Expiry date | May 22, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60Q1/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved dual polarity substitution circuit for energizing a secondary load, such as an incandescent lamp, upon failure of a primary load. Dual polarity is achieved through the use of parallel PNP and NPN transistors, one of which conducts so long as the primary load is functional. Upon failure of the primary load and interruption of current flow in the conducting one of the transistors, a bidirectional switch such as a triac is fired to energize the secondary load.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.