Coupled oscillatory circuit for vehicle detection

Abstract

The invention discloses a coupled oscillatory circuit for vehicle detection. The coupled oscillatory circuit includes a resistor R1, resistors from R2 to R6, a coupling transformer T1, a loop coil L, a comparator A, diodes of D1 and D2, a transient voltage suppressor D and two power source lightning protectors; the loop coil L is connected between an a end and a b end of the coupling transformer T1; the transient voltage suppressor D is connected in parallel at two ends of the loop coil L; the diode D1 and the diode D2 are sequentially connected in series between a c end and a d end of the coupling transformer T1, wherein the diode D1 and the diode D2 are in reverse connection with each other; the c end of the coupling transformer T1 is also connected with the resistor R4 and the collector of a triode T simultaneously; the base of the triode T is connected with the resistor R1 and a power source VCC sequentially; and the emitter of the triode T is connected with the resistor R3, the power source lightning protectors and the power source VCC sequentially. With the above coupled oscillatory circuit adopted, damage which is caused by intrusion of lightning and other internal voltage can be avoided, and the transformer can be prevented from being damaged by transient high voltage, and therefore, the stability of a vehicle detector can be improved, and the service life of the vehicle detector can be prolonged.

Description

technical field [0001] The invention relates to the field of vehicle detection, in particular to a coupling oscillation circuit for vehicle detection. Background technique [0002] With the development of the economy, intelligent transportation has quietly emerged in our country. As an important part of traffic information collection, vehicle detectors have attracted more and more attention from the industry. The vehicle detector takes the motor vehicle as the detection target, detects the passage or existence of the vehicle, and its function is to provide sufficient information for the intelligent traffic control system to perform optimal control. At present, the commonly used vehicle detectors in the world mainly include loop coil vehicles. Detectors, video vehicle detectors and microwave vehicle detectors, among which toroidal coil vehicle detectors are widely used due to their high accuracy, low cost, and high reliability. In the vehicle detector, it is usually necessar...

AI Technical Summary

Problems solved by technology

In the vehicle detector, it is usually necessary to add a coupling oscillation circuit. In the coupling oscillation circuit, transformers, transistors, etc. are needed. However, the transformers and transistors in the coupling oscillation circuit in the vehicle detector are easily damaged by instantaneous high voltage, and The oscillating circuit is easily damaged by lightning and other internal overvoltage intrusion into the equipment, which affects the service life of the vehicle detector

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