电振音叉说明书J-SB2型

User’s Manual for J-SB2 Fork Oscillator

用途：

Application:

供大专学校基础物理实验，作迈尔德氏弦振动试验之用。

Specially used for Maier De's string vibration test in fundamental physics experiment of universities and colleges

结构及基本性能：

Structure and basic properties:

       本仪器为一大型音叉，由整块的钢材切削而成。在两叉枝的顶端，装置记录笔尖一对，以供记录波纹之用。叉柄固着于木质底板上的Ω型底坐上，在两叉枝间距叉顶约三分之一处，装置一电磁铁，在左侧叉枝的外侧配备断续接触器，接通电流后，配合音叉的振动，形成励磁线圈断续通电，致使电磁铁产生间断吸力，驱使音叉作长期的振动。本音叉频率约为100周/秒，每具音叉的实际频率数均用硬印标出。标出的频率数据就是是音叉顶部装有一对记录笔尖的频率，如将此等附件连同螺丝全部卸去，则频率约增加4分之3周。由于音叉叉枝质量较大，故在实验中如弦振动驻波试验等，负荷稍有变动时，对频率的影响不大。

This instrument is a large tuning fork made from the cutting of one-piece steel material. A pair of recording pen-points is mounted at the top of two branches for the purpose of recording ripples. Fork handle is fixed on the Ω type seat of wooden bottom plate, one electromagnet is arranged between two fork branches and about one third away from the fork top, and an intermittent contactor is mounted at the outside of left-side fork branch. After the power supply is switched on, it is possible to form excitation coil, provide intermittent electricity, cause the electromagnet to produce intermittent suction, and drive the tuning form to produce long-term vibration. The frequency of tuning fork is 100 cycle per second, and the actual frequency number of each of tuning fork is marked with embossing seal. The marked frequency data equals to the frequency of a pair of recording pen points mounted at the top of tuning fork, and the frequency may increase 3/4 cycle, provided that these accessories and other screws are compley dismantled. Due to the larger mass of tuning form branch, slight changes in load may not have significant impact on frequency in such experiment as string vibration standing wave test.

使用方法：

Use Method:

       将本仪器底板上所附电源输出叉头接在底板的接线柱上（或根据需要另接电源），调节断续器接触点螺丝，使音叉维持稳定振动，叉端振幅约达1.5m/m。调节适度后，即将螺帽固紧使不至松动。一次调节后如所用电源的电压不变，则以后使用时可不必再行调节。在使用时如音叉呈静止状态,则断续器不能起正常的作用。故在接通电流时，可轻敲叉枝，协助音叉起动。

   Connect the power output plug (attached on the bottom plate of this instrument) onto the terminal of bottom plate (or otherwise connect to power as required), regulate the contact point screw of interrupter to enable the tuning fork to maintain steady vibration, and the fork-side amplitude may reach 1.5m/m. After an appropriate adjustment, it is necessary to tighten the screwed cap and avoid looseness. Readjustments are not required in the later uses, provided that the voltage of power supply remains unchanged after the first time of adjustment. The interrupter can not play a normal role if the tuning fork is in resting state during application. Therefore, it is possible to gently strike the fork branch to help the start of tuning fork when the current is switched.

       本音叉叉枝的顶端有螺丝，作迈尔德氏弦振动试验时，可将弦线一端用螺丝固着。

    Screw is mounted at the top of tuning fork branch, and it is possible to fix one end of string with screw when Maier De's string vibration test is being conducted.

仪器的保管：

Storage of Instrument:

       音叉的叉枝上如发生锈蚀等变化或附着厚层油污，能直接影响音叉的频率，故在使用之前，须以柔软纱布将油污楷试洁净，在使用完毕之后，须遍涂防锈油，音叉须放置于干燥处，以防锈蚀。

The frequency of tuning fork may be directly affected if erosion and other changes exist in the fork branch of tuning fork, or the branch is covered with thick oil stain. For this regard, it is necessary to use soft gauze to wipe off the oil stain before the application of this instrument. Moreover, it is also necessary to coat anti-rust oil throughout the instrument after the completion of application. The tuning fork must be stored at dry place to avoid corrosion.

重量：…………………………………………………………………………………….约3.5公斤

Weight: ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..  About 3.5 kg

外形尺寸:………………………………………………………………….音叉叉枝长约300毫米

Dimension:                       Length of tuning fork branch is about 300mm

                                                           厚约       8毫米

                                                           Thickness    8 mm

                                                           宽约     23毫米

                                                           Width    23 mm

                                                           木底板  160x395毫米

                                                  Wooden bottom plate 160x395 mm