DE2827174A1 - Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential - Google Patents

Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential

Info

Publication number
DE2827174A1
DE2827174A1 DE19782827174 DE2827174A DE2827174A1 DE 2827174 A1 DE2827174 A1 DE 2827174A1 DE 19782827174 DE19782827174 DE 19782827174 DE 2827174 A DE2827174 A DE 2827174A DE 2827174 A1 DE2827174 A1 DE 2827174A1
Authority
DE
Germany
Prior art keywords
triac
projector
control circuit
switch
brightness control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE19782827174
Other languages
German (de)
Inventor
Josef Weber
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to DE19782827174 priority Critical patent/DE2827174A1/en
Publication of DE2827174A1 publication Critical patent/DE2827174A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B39/00—Circuit arrangements or apparatus for operating incandescent light sources
    • H05B39/04—Controlling
    • H05B39/08—Controlling by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices
    • H05B39/083—Controlling by shifting phase of trigger voltage applied to gas-filled controlling tubes also in controlled semiconductor devices by the variation-rate of light intensity

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

A brightness control circuit is for a projector lamp. The lamp (2) has a triac (4) in series which has a control circuit (3) and an adjustable resistor (5). The triac (4) can be shorted out by a parallel switch (7). This arrangement removes residual voltage on the triac so that max. brightness can be achieved.

Description

Projektor mit einer HelligkeitssteuerungProjector with a brightness control

Die Erfindung betrifft einen Proåektor mit einer Helligkeitssteuerung für die Projektorlampe unter Verwendung einer einen Triac aufweisenden Schaltungsanordnung, der im Stromkreis der Projektionslampe liegt.The invention relates to a proåektor with a brightness control for the projector lamp using a circuit arrangement having a triac, which is in the circuit of the projection lamp.

Bei diesen Projektoren ist es bekannt, daß bei voller Ansteuerung des Triacs zur Erzielung der größtmöglichen Lichtstärke eine Restspannung am Triac verbleibt, die eine mehr oder weniger große Minderung der Lichtleistung der Projektionslampe ergibt. Es ist zwar versucht worden, durch die AnwSdung von Transformatoren mit höheren Ausgangs spannungen die Restspannung am Triac zu kompensieren. Dies führt jedoch bei Beachtung elektrischer Bestimmungen zu komplizierten Ausgestaltungen für den Projektor.With these projectors it is known that when fully controlled of the triac to achieve the greatest possible light intensity, a residual voltage on the triac remains, which is a more or less large reduction in the light output of the projection lamp results. Attempts have been made by using transformers with higher output voltages to compensate for the residual voltage on the triac. this leads to however, if electrical regulations are complied with, they lead to complicated configurations for the projector.

Es ist Aufgabe der Erfindung Maßnahmen zu schaffen, die eine Regelungsmöglicbkeit bis zur vollen Lichtleistung der Proj ektionslampe ermöglichen.It is the object of the invention to create measures that allow for regulation Allow up to the full light output of the projection lamp.

Der Erfindung gemäß ist diese Aufgabe gelöst durch die Anordnung eines zum Triac parallelen Stromkreises mit einem Uberbrückungsschalter für den Triac. Bei offenem Uberbrückungsschalter ist die Regelung in bekannter Weise vermittels eines den Triac ansteuernden Drehwiderstandes möglich, während der geschlossene Schalter ohne großen Aufwand die volle Ausgangsspannung des Transformators unmittelbar an die Projektionslampe legt. Bei bevorzugter Ausbildung ist der UberbrUckungsschalter durch das Drehglied des Drehwiderstands betätigbar dergestalt, daß im Endbereich der Hellstellung der Uberbrückungsschalter bei weiterer Betätigung schließbar ist. According to the invention, this object is achieved by the arrangement a circuit parallel to the triac with a bypass switch for the Triac. When the bridging switch is open, the control is mediated in a known manner a rotary resistance controlling the triac is possible, while the closed Switch directly to the full output voltage of the transformer without great effort to the projection lamp. The bridging switch is the preferred embodiment can be actuated by the rotary member of the rotary resistor in such a way that in the end region the bright position of the bypass switch can be closed upon further actuation.

Es entspricht der Erfindung, daß Projektoren mit einer Triac-Regelschaltung für die Projektionslampe auch mit dem Uberbrükkungsschalter nachgerüstet werden können. Die Verbindung von Drehwiderstand und Uberbrückungsschalter wirkt sich schließlich auch günstig auf den Einschaltstromstoß aus.It corresponds to the invention that projectors with a triac control circuit for the projection lamp can also be retrofitted with the bypass switch can. The connection of the rotary resistor and the bypass switch ultimately has an effect also has a favorable effect on the inrush current.

Die Erfindung ist in der Zeichnung schematisch verdeutlicht.The invention is illustrated schematically in the drawing.

Hierin ist mit 1 ein Transformator und mit 2 die Projektionslampe eines Projektors bezeichnet. Zur Regelschaltung 3 für die Helligkeit der Projektionslampe 2 gehört ein Drehwiderstand 5 und ein Triac 4. Letzterer liegt in bekannter Weise mit der Projektionslampe in Reihe. In einem zum Triac 4 parallelen Stromkreis 6 ist ein Überbrückungsschalter 7 vorgesehen, der in der Schließstellung den Triac überbrückt und damit die volle Transformatorausgangsspannung an die Projektionslampe 2 legt.Here with 1 is a transformer and with 2 the projection lamp of a projector. To control circuit 3 for the brightness of the projection lamp 2 includes a rotary resistor 5 and a triac 4. The latter is in a known manner in series with the projection lamp. In a parallel to the triac 4 Circuit 6, a bypass switch 7 is provided, which in the closed position the triac bridged and thus the full transformer output voltage to the projection lamp 2 sets.

Claims (3)

Patentansprüche 1. Projektor mit einer Helligkeitssteuerung für die Projektionslampe unter Verwendung einer einen Triac aufweisenden Schaltungsanordnung, der im Stromkreis der Projektionslampe liegt, gekennzeichnet durch die Anordnung eines zum Triac (4) parallelen Stromkreises mit einem Überbrückungsschalter (7) für den Triac (4). Claims 1. Projector with a brightness control for the Projection lamp using a circuit arrangement having a triac, which is in the circuit of the projection lamp, characterized by the arrangement a circuit parallel to the triac (4) with a bypass switch (7) for the triac (4). 2. Projektor nach Anspruch 1, dadurch gekennzeichnet, daß der Überbrückungsschalter durch das Drehglied eines zur Regelschaltung gehörenden Drehwiderstandes (5) betätigbar ist.2. Projector according to claim 1, characterized in that the bypass switch can be actuated by the rotary member of a rotary resistor (5) belonging to the control circuit is. 3. Projektor nach einem oder beiden der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Überbrückungsschalter (7) oder das Betätigungsglied für diesen am Projektorgehäuse außen angeordnet ist.3. Projector according to one or both of the preceding claims, characterized in that the bridging switch (7) or the actuating member for this is arranged on the outside of the projector housing.
DE19782827174 1978-06-21 1978-06-21 Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential Withdrawn DE2827174A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19782827174 DE2827174A1 (en) 1978-06-21 1978-06-21 Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19782827174 DE2827174A1 (en) 1978-06-21 1978-06-21 Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential

Publications (1)

Publication Number Publication Date
DE2827174A1 true DE2827174A1 (en) 1980-01-10

Family

ID=6042342

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19782827174 Withdrawn DE2827174A1 (en) 1978-06-21 1978-06-21 Brightness control circuit for projector - has triac which can be shunted by switch to remove residual potential

Country Status (1)

Country Link
DE (1) DE2827174A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5658062A (en) * 1994-09-23 1997-08-19 Lg Electronics Inc. Light amount controlling apparatus and method for projector
DE102010013336A1 (en) 2010-03-30 2011-01-05 Daimler Ag Device for recording master images with the help of camera, has video projector by which master images are projected, where video projector is coupled with image data unit by which master images are guided to video projector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5658062A (en) * 1994-09-23 1997-08-19 Lg Electronics Inc. Light amount controlling apparatus and method for projector
DE102010013336A1 (en) 2010-03-30 2011-01-05 Daimler Ag Device for recording master images with the help of camera, has video projector by which master images are projected, where video projector is coupled with image data unit by which master images are guided to video projector

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Legal Events

Date Code Title Description
8139 Disposal/non-payment of the annual fee