Abstract: A circuit arrangement includes a programmable memory element mounted on a circuit board, with programming contacts of the memory element connected to conductor paths of the circuit board. Data and/or programming codes stored in the memory element determine the functions of the circuit arrangement. To prevent unauthorized reprogramming of the memory element, at least one programming contact of the memory element and each conductor path connected thereto are covered or enclosed, so it is impossible to electrically contact this programming contact or the associated conductor paths without destroying the circuit arrangement. The circuit board is adhesively bonded to a board carrier, with the memory element and conductor paths sandwiched or encased therebetween. The circuit arrangement may be an engine controller for a motor vehicle, with security against unauthorized reprogramming for altering the performance of the engine.

Abstract: A circuit arrangement includes a programmable memory element mounted on a circuit board, with programming contacts of the memory element connected to conductor paths of the circuit board. Data and/or programming codes stored in the memory element determine the functions of the circuit arrangement. To prevent unauthorized reprogramming of the memory element, at least one programming contact of the memory element and each conductor path connected thereto are covered or enclosed, so it is impossible to electrically contact this programming contact or the associated conductor paths without destroying the circuit arrangement. The circuit board is adhesively bonded to a board carrier, with the memory element and conductor paths sandwiched or encased therebetween. The circuit arrangement may be an engine controller for a motor vehicle, with security against unauthorized reprogramming for altering the performance of the engine.

Abstract: A circuit arrangement for independently switching the induction coils of several d.c.-operated solenoid valves connected in parallel that, with a reduction of power loss, features a disconnection time which is independent of the voltage of the d.c. voltage source.

Abstract: A circuit configuration for the evaluation of inductive sensor signals in motor vehicles is described. An input stage comprising an input circuit and a reference circuit and a threshold value stage comprising a peak value rectifier circuit, converter circuit, comparator circuit, and adjustment circuit are provided for the recognition of the crossover of an alternating voltage sensor signal.