The invention relates to a connector for detachably connecting together an electrical unit and an article. Such a connector comprises a housing with two insertion openings that define a receiving chamber. Within this receiving chamber are arranged two opposing contacts which protrude beyond the housing and are electrically connected to one another when the connector is mounted on the article. Also, the contacts are electrically connected to a power source located outside the connector. When the article is not connected to the connector, the contacts are not electrically connected to one another. To establish contact with the power source, the connector can be inserted into a corresponding insertion opening of the electrical unit, in which case the contact with the power source can be made by inserting the connector into the insertion opening of the electrical unit, and by providing that the housing, with its insertion openings, is likewise oriented in a way such that the connector can be inserted into an insertion opening of the electrical unit. In this way, a corresponding electrical circuit is established between the article and the power source, which is connected to the contacts within the connector. The object of the present invention is to provide a connector that can be used with a single, standard connector part. In other words, the connector should allow the electrical power supply to an article that can be mounted in various locations to be selected from various commercially available power sources. The present invention is also intended to be sufficiently flexible in order to be able to be used for various articles of different types. Moreover, the connector should be easily inserted into an insertion opening. Moreover, the present invention is intended to allow the connection to be disconnected in a simple way. The above object is attained by a connector that includes a first and second connector part, and has at least one insertion opening. A contact is accommodated in the first connector part, which is connected to the power source. The contact can establish electrical contact with the power source when the first connector part is in electrical contact with the second connector part. The connector is constructed so that the first connector part can be inserted in a corresponding insertion opening of an electrical unit, and at the same time be secured against it, such that an electrical connection with the contact is formed between the first connector part and the contact. In the process, it is possible to connect the second connector part to the first connector part, as a result of which the electrical connection between the power source and the contact is established. The first connector part can be detached from the second connector part in a simple way, whereby the connection between the power source and the electrical unit is interrupted. To accomplish this object, the present invention can be used in combination with a plurality of different insertion openings, wherewith the power source can be connected in accordance with the desired function. In this case, the connector can be used for various articles. In a further refinement, the connector comprises an insulator, on which at least one contact made of electrically conductive material is secured. At least one of the contacts has a portion that extends from the insulator. A counter contact is provided, which is intended to be secured to an electrical unit and to cooperate with the contacts of the insulator for the purpose of forming electrical contact with a power source. To accomplish this object, the present invention can be used in combination with a plurality of different insertion openings, wherewith the power source can be connected in accordance with the desired function. In a further refinement, the first connector part is formed as a module. The module comprises an insulator, on which at least one contact made of electrically conductive material is secured. The contact has a portion extending from the insulator. A counter contact is provided, which is intended to be secured to an electrical unit and to cooperate with the contacts of the insulator for the purpose of forming electrical contact with a power source. The insulator is constructed as a separate unit. The first connector part is connected to the insulator. Another object of the present invention is to provide a connector that can be easily mounted and disassembled by hand. For this purpose, the connector is inserted into an insertion opening of an article, and is secured against it. In a further refinement, the connector comprises an insulator. A portion of the insulator has at least one notch extending into it from a side edge of the insulator. The notch is intended to receive a finger of the hand for mounting and disassembling the connector. Another object of the present invention is to provide a connector that can be quickly mounted and disassembled by hand. For this purpose, the connector is inserted into an insertion opening of an article, and is secured against it. In a further refinement, the connector comprises an insulator. A portion of the insulator has at least one notched section extending into it from a side edge of the insulator. The notched section is intended to receive a finger of the hand for mounting and disassembling the connector. Another object of the present invention is to provide a connector that can be formed by injection molding, such that it can be easily produced as a standard part. In this way, a large variety of different articles can be provided with a connector according to the present invention, whereby each different type of article can be connected to one or more corresponding power sources. To accomplish this object, a first connector part is configured to be insertable into an insertion opening of an electrical unit, and is constructed to electrically connect to a power source. The connector has a housing with at least one insertion opening, on which the first connector part is placed and secured against it. At least one contact is accommodated within the housing, and is electrically connected to the first connector part. The contact protrudes beyond the housing and is oriented toward the power source. In this case, the connector is constructed so that it can be produced by injection molding. The object is also attained by a connector that comprises a second connector part and has at least one insertion opening. A contact is accommodated in the second connector part, which is connected to the power source. The contact can establish electrical contact with the power source when the second connector part is in electrical contact with the first connector part. The connector is constructed so that the first connector part can be inserted in a corresponding insertion opening of an electrical unit, and at the same time be secured against it, such that an electrical connection with the contact is formed between the first connector part and the contact. In the process, it is possible to connect the first connector part to the second connector part, as a result of which the electrical connection between the power source and the electrical unit is established. The first connector part can be detached from the second connector part in a simple way, whereby the connection between the power source and the electrical unit is interrupted. To accomplish this object, the present invention can be used in combination with a plurality of different insertion openings, wherewith the power source can be connected in accordance with the desired function. In this case, the connector can be used for various articles. In a further refinement, the first connector part is formed as a module. The module comprises an insulator, on which at least one contact made of electrically conductive material is secured. The contact has a portion extending from the insulator. A counter contact is provided, which is intended to be secured to an electrical unit and to cooperate with the contacts of the insulator for the purpose of forming electrical contact with a power source. The insulator is constructed as a separate unit. The first connector part is connected to the insulator. A further object