U.S. Philips Corporation

Wieger Lindeboom

Peter Sofrides Viet

Oedilius Johannes Bisschop

Jan Tiesinga

A battery charger whose charging current is shut off on the basis of the temperature difference between the ambient temperature, measured by means of a first sensor (R.sub.A), and the battery temperature, measured by means of a second sensor (R.sub.B). The error in the measurement of the temperature difference, which is caused by the input voltage dependent heat generation by the power supply (PS) in the battery charger, is compensated by a third signal (k*V.sub.i) which is representative of the anticipated additional heat generation as a result of a varying input voltage (V.sub.i).

Battery charger with charging current variation based on a temperature

A dual-slope measuring circuit for measuring an unknown resistance. A first time measurement measures the time which is needed to charge a capacitor to a first reference voltage (Uref.sub.1) via a reference resistor. A second time measurement measures the time which is needed to charge the capacitor again to the first reference voltage (Uref.sub.1) but now via the parallel arrangement of the reference resistor and the unknown resistance. The value of the unknown resistance is determined from the ratio between the two time intervals thus measured. The time measurement is not started until the capacitor voltage (Uc) on the capacitor has passed a second reference voltage (Uref.sub.2), where the second reference voltage has a value between the first reference voltage and the capacitor voltage (Uc) appearing across the capacitor immediately after discharge of the capacitor.

Resistance measuring circuit, and thermal apparatus including the

A vacuum cleaner is provided which has a motor housing (2) and a hose (8), which can be coupled via two mains-voltage wires (38, 42), one communication wire (48) and contacts (32, 34, 30). The motor housing (2) and the handle (10) of the hose (8) include microprocessors (6, 12) which communicate with one another via the communication wire (48). The first reference signal (26) of the one microprocessor (6) is connected to the one mains voltage terminal (18) and the second reference signal (44) of the other microprocessor (12) is connected to the other mains voltage terminal (40).

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Drachten, Netherlands

Wieger Lindeboom