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一、做电磁波发射和接收的演示在缺乏仪器的农村中学,教师可用收音机对学生做电磁波发射和接收的演示。找甲、乙两台中波段晶体管超外差式收音机,甲机作发射机,乙机作接收机用。作发射机用的甲机需作如下简单改接。 1.将磁性天线次级线圈两端连接,短路外来信号。 2.将喇叭与输出变压器次级不接地的一端的连接处断开,并将音量控制电位器与检波级相连的一端断开;然后,将喇叭断开的一端接在电位器断开的一端;将输出变压器次级断开的一端串一个30μF电容器接到
First, to do the demonstration of electromagnetic wave emission and reception In rural schools lack of instrumentation, teachers can use radios to do the demonstration of electromagnetic wave emission and reception to students. Find A, B two medium-band transistor super-heterodyne radio, a machine for the transmitter, B receiver for use. A machine for the transmitter needs to be as follows a simple change. 1. The magnetic antenna secondary coil connected to both ends, short-circuit external signals. 2. The speaker and the output transformer secondary ungrounded one end of the connection is disconnected, and the volume control potentiometer and the detection stage connected to one end is disconnected; then, the speaker disconnect the end of the potentiometer disconnect the end Connect a 30μF capacitor to the secondary side of the output transformer