Electrical LC resonant circuit
AssigneeSiemens Aktiengesellschaft
InventorsReinhard Behn, Harald Loebl, Karl-Heinz Preissinger
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Abstract
An electrical LC resonant circuit, particularly useful for channel filters in carrier frequency technology, has a fixed-tuned coil and a capacitor tunable by the removal of layer surface portions. The capacitor is constructed as an essentially flat, self-healing layer capacitor having a relatively small number of layer surfaces and dielectric layers lying one upon the other.
Claims12
An arrangement of coils and capacitors for narrow tolerance resonant circuits in channel filters in the carrier frequency technology within the frequency range of between approximately 10 and 100 kHz, comprising:
- (a) a mounting plate carrying and connecting the coils and capacitors;
- (b) at least one fixed-tuned coil whose inductance is set in a fixed non-adjustable manner, said coil having a magnetic core and at least one wire winding;
- (c) at least one self-healing laser trimmable capacitor comprising a flat stack of at least two metal layers which are separated by a dielectric layer and which are covered by a laser light permeable non-destructing cover film, at least two connecting wires contacting with the metal layers, the self-healing capacitor being oriented towards an edge of the base plate with respect to the fixed-tuned coil so that at least a first of the metal layers can be burned off through the cover film by means of an incident laser beam, said fixed-tuned coil being positioned inwardly of the self-healing capacitor from the edge of the mounting plate, said laser-trimmable capacitor cover film being substantially undamaged when the capacitor is trimmed by a laser beam;
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- (d) a narrow-tolerance channel-filter resonant circuit being formed which includes said fixed-tuned coil and self-healing capacitor and has a resonant frequency within the frequency range of approximately 10 to 100 kHz, any additional coils forming the resonant circuit being fixed tuned and non-adjustable.
An LC resonant circuit of narrow tolerance for use as a channel filter, comprising:
- (a) a mounting plate;
- (b) a fixed-tuned coil on the plate whose inductance is set in a fixed non-adjustable manner, said coil having a ferrite core which has not been processed by grinding for tuning the coil;
- (c) a self-healing laser trimmable capacitor comprising a flat stack of at least two metal layers which are separated by a dielectric layer and which are covered by a laser light permeable non-destructing cover film, connecting wires on the capacitor connecting to the fixed-tuned coil, said self-healing capacitor being positioned on the mounting plate to permit direct exposure of one of said metal layers to a laser beam to permit burn-off of portions of the metal layer through the cover film without substantial damage to the cover film;
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- (d) a narrow-tolerance channel filter resonant circuit which includes said coil and capacitor and which has a resonant frequency within the frequency range of approximately 10 to 100 kHz, any additional coils forming the resonant circuit being fixed tuned and non-adjustable.
Dependencies are inferred from the claim text.