Untitled Document

Physics Demo Number: 175

Approximate

Run Time 5 min

Transient Induced Current in a Coil Associated with a Change of DC Current In an Inner Coil

Demo Description

View the transient induced currents in a coil which occur as a result of a DC current being established or broken in a solenoid enclosed by the coil.

Scientific Principles

Transient currents can be induced by the birth or the death of a DC current, as well as by AC currents.

Equipment

Overhead projector meter
Dedicated solenoid/coil pair

Equipment Location

Kit(133) on [B-2-6], shares same box with
Kit(175) on [B-2-6]

Instructions

The dedicated apparatus seen in the first photo was assembled by Dave Burba and Julia Velkovska to show the transient induced currents in a coil on the outside of a solenoid when a DC current is being established or terminated in the solenoid by making or breaking the connection of the solenoid terminals to a 6V battery.

The second photo shows a closer view of the overhead projector meter , borrowed from (133) , used to show the evidence of the transient currents on the lecture hall screen.

The third photo gives a closer look at the solenoid and outer coil wrapper.

The solenoid consists of the tightly wound enameled wire, with terminals at the bottom of photo for connecting to the battery. The homemade outer coil (made from red plastic insulated wire) is wound in the same sense as the solenoid and has its ends outputing to the hook- up wires at the top of the photo.