U.S. Philips Corporation

Klaas J Lulofs

Roelf Van Der Wal

Jacob H Botma

Petrus J Bremer

Tjerk Bij De Leij

A toaster has heating elements (H1, H2) arranged at opposite sides of a product (5) to be toasted. The size of the product to be toasted (5) is detected by a sensor, for example a mechanical sensor (2.1, 2.2, 2.3) or an optical sensor device with a photo-emitter and a photo-receiver. The power delivered by the heating elements (H1, H2) is controlled in dependence on the detected size. Thus, the power consumption of the toaster is adapted to the size of the product to be toasted and overheating of the product is avoided and a constant toasting time is obtained.

Toaster with power output control

A hot-air appliance comprises a fan motor connected in series with a heating element to receive a.c. mains voltage. The alternating voltage across the motor is rectified and serves to power additional electronic circuits in the appliance.

Low-voltage generation in mains-powered hot-air appliances having a fan

An RC oscillator having an oscillation frequency which is controllable by supplying a step voltage signal to a series arrangement of a capacitor and a resistor, the oscillation frequency being dependent on the time for the capacitor to be charged to a given voltage level. In order to vary the frequency, the amplitude of the supplied step voltage is varied instead of the resistance of the resistor via which the capacitor is charged. The amplitude variation can be provided, for example, by a potentiometer which acts as a voltage divider for the step voltage. The tolerance of the potentiometer in regard to its resistance value will not be relevant, because it is only the ratio between different portions thereof which is determinative. The step voltage, and consequently the oscillation frequency, will be proportional to the setting of the potentiometer regardless of the resistance tolerance thereof.

Timer with adjustable time control based on an RC oscillator with a

A hair-care appliance measures the moistness of the hair by measuring the resistance (R.sub.x) of the hair between measurement electrodes (14A/14B). The hair resistance (R.sub.x) is included in a T network comprising a first resistor (20) driven by a voltage source (28) and a second resistor (24). The signal current (I.sub.s) through the second resistor is measured and converted into a measurement signal (MS) by a converter (30). As a result of the use of the T network a comparatively large resistance variation of the hair resistance (R.sub.x) is required for a given amplitude variation in the signal current (I.sub.s). This allows measurements over a wider resistance range while the resolution is maintained.

Hair-care appliance with hair-moistness measurement by measuring the

A Toaster having heating elements whose heating area depends on the slice size. A toaster has heating elements (H1, H2) divided into sub-elements (H1A, H1B; H2A, H2B) which can be activated individually. The size of the product to be toasted (5) is detected by means of a sensor, for example a mechanical sensor (2) or an optical sensor device with a photo-emitter and a photo-receiver. The sub-elements are activated selectively in dependence on the detected size. Thus, the power consumption of the toaster is adapted to the size of the product to be toasted and overheating of the product in the proximity of the unused heating area of the heating elements is avoided.

Growing community of inventors

Drachten, Netherlands

Klaas J Lulofs