Abstract: This is a radar transponder in which an amplifying means using a FET amplifier is inserted between a receiving antenna and a detecting means. Further, the radar transponder has a receiving on/off control circuit which stops the operation of the amplifying means in transmitting a response signal in order to enhance the receiving sensitivity thereof. Also, the radar transponder mounts the amplifying means, and the detecting mounts the amplifying means, and the detecting means via a metal body having resilience on an antenna housing. Each circuit unit of the radar transponder and connection wirings between each circuit unit are formed by flexible printed circuit boards.

Abstract: A radar transponder comprising:a control circuit for controlling transmission and reception of signals in order to receive a receiving signal and transmit a definite answer signal,a video amplifier for amplifying the detection signal of the receiving signal, andan auxiliary video amplifier for amplifying the amplified output signal up to the level allowing the control circuit to be triggered,the radar transponder providinga video switch between the amplifier and auxiliary amplifier and switched in such a manner that a signal input to the auxiliary amplifier is broken only during the transmitting period of the answer signal by feeding back a positive potential pulse synchronized with the output signal from the control circuit and an input signal applied to the auxiliary amplifier is conducted except during the transmitting period of the answer signal, thereby delivering an output signal of the video amplifer to the auxiliary amplifier, andfurther, on respect, a pulse stretcher circuit between the control circu

Abstract: A main body has a partition wall provided in the interior of the main body and a communication hole formed in the wall. A valve body is disposed in the main body to be movable between a first position and a second position. At the first position the valve body closes the hole, and at the second position the valve body opens the hole. A spring urges the valve body into the second position. An operating lever is connected in a universal-joint fashion to the main body. A cam is formed on the lever and slidably contact with a cam contact element disposed on the valve body in a position away from a plane including a center axis of the main body. A pair of grooves are formed on the lever at each side of the cam and extend along the plane. A pair of projections are provided on the valve body and inserted into the grooves. When the lever is rotated in one or the other direction in the plane by an external force, the valve body is moved between the first and the second position by the action of the cam.