The solenoid

A cylindrical coil, having a movable ferromagnetic core, can be useful for various things. This is a solenoid. Electrical relays, bell ringers, electric “hammers,” and other mechanical devices make use of the principle of the solenoid.

A ringer device

Figure 1 is a simplified diagram of a bell ringer. Its solenoid is an electromagnet, except that the core is not completely solid, but has a hole going along its axis. The coil has several layers, but the wire is always wound in the same direction, so that the electromagnet is quite powerful. A movable steel rod runs through the hole in the electromagnet core.

Figure 1: A solenoid-coil bell ringer.

When there is no current flowing in the coil, the steel rod is held down by the force of gravity. But when a pulse of current passes through the coil, the rod is pulled forcibly upward so that it strikes the ringer plate. This plate is like one of the plates in a xylophone.
The current pulse is short, so that the steel rod falls back down again to its resting position, allowing the plate to reverberate: Gonggg! Some office telephones are equipped with ringers that produce this noise, rather than the conventional ringing or electronic bleeping ernitted by most phone sets.

مواضيع ذات صلة

الحساسات النانوية لرصد وتعقب حرائق الغابات

التكامل بين تكنولوجيا النانو وتكنولوجيا الاستشعار من بعد لرصد تلوث الهواء الجوي

الحساسات النانوية للحالة الصلبة

الحساسات النانوية لرصد ملوثات الهواء

تكنولوجيا النانو وصناعة الحساسات

الحساسات النانوية

تقنية النانو في الطباعة على الأسطح Nano–Lithography

تقنية الطباعة على الأسطح Lithography

التنافس العالمي في إنتاج الحاسبات المعتمدة على تكنولوجيا النانو

قانون مور

تركيب الترانزستور وكيفية عمله

ماهية الترانزستورات