Global Patent Index - EP 0054407 A1

EP 0054407 A1 19820623 - Load current protection circuit.

Title (en)

Load current protection circuit.

Title (de)

Laststromschutzschaltung.

Title (fr)

Circuit de protection d'un courant de charge.

Publication

EP 0054407 A1 19820623 (EN)

Application

EP 81305812 A 19811209

Priority

GB 8039358 A 19801209

Abstract (en)

There is disclosed a device to protect against failure of a switch S and to give an alarm that the switch has failed. It comprises a circuit in parallel with the switch and containing a transistor T2 and diode D1 to cause such voltage drop in the circuit as to prevent current flowing through a second diode D2 when the switch S is closed. If the switch fails open, the potential at B will drop, and diode D2 will allow current to flow to the load L through the circuit. The current flow produces a potential difference across diode D1 to turn on another transistor T1 to cause an alarm to be given. The device may be used to test such switches without affecting the load controlled by the switch.

IPC 1-7

H02H 3/04; G08B 29/00

IPC 8 full level

G08B 29/14 (2006.01); G08B 29/18 (2006.01); H01H 47/00 (2006.01)

CPC (source: EP)

G08B 29/14 (2013.01); G08B 29/22 (2013.01); H01H 47/002 (2013.01)

Citation (search report)

Designated contracting state (EPC)

BE DE FR IT NL SE

DOCDB simple family (publication)

EP 0054407 A1 19820623; EP 0054407 B1 19851023; DE 3172734 D1 19851128; GB 2089591 A 19820623; GB 2089591 B 19850522

DOCDB simple family (application)

EP 81305812 A 19811209; DE 3172734 T 19811209; GB 8039358 A 19801209