| 摘要 |
The invention relates to a circuit arrangement for theft protection for electronic receiving or transmitting systems, particularly for car radio sets, using a key activating an electronic circuit arrangement and allowing authorized taking-into-operation, this key, as electronic key (S), containing switching elements (R1, R2) of an electronic circuit (R1-R5) which is only complete when the key is inserted and is thus neutral and does not impede the taking-into-operation and which, in the non-neutral operating state switches the set into a permanent non-operational state. For this purpose, the key (S) is constructed as jack plug which can be plugged into an associated jack socket. The key preferably contains two resistors (R1, R2) of a resistance bridge which is in equilibrium and which is balanced together with resistors (R3, R4) contained in the set.
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