Apparatus for experimental research with magnetism in biomedicine and biota.
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The apparatus shown in the picture is based on a very simple electrical circuit; basically it is just three components: a toroidal coil and a lamp* connected in series and a double-throw commutator yet it offers many possibilities for experimentation with magnetic fields.

In the present configuration there are two toroidal coils, respectively 56 and 70 cm. inner diameter, iron core. It operates from a variable power supply based on a Variac autotransformer, from 0 to 230 volts 50 cps alternate current (AC) and from 0 to 40 volts full wave direct current (DC).

 

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The coils can be powered independently of one another either on AC or DC, while the lamps in the circuitry and the variable power supply allow a choice of the desired power in Watts; one coil is mounted on a slider so that the distance between the two coils can be varied from 40 cm to almost adjacency. The two coils can also be powered, on DC only, in a series configuration; they can also be completely disconnected and redirected to external circuitry.

Operating power is deducible from the meters's readings while a compass needleís deflection (up to about 50į) shows smoothly that they operate properly in accordance with the supplied voltage. Presently I donít have a magnetometer (Gauss Meter), indispensable to properly experiment with it.

Additionally, the smaller coil has an 8 ohms (resistance) winding** on an interlaced ferrite nucleus which can be substituted to an amplifier's speaker or get input from an audio-frequency (AF) generator, a pulse generator, or a computer using AF generator software (example: Audacity, open source) so that desired AFs can be superimposed on the coilís voltage; in this case battery operation (pure DC) is preferable to the 50 0r 60 cps AC operated power supply only if some external waveform is superimposed since static magnetic fields are not recommended. In between the smaller toroidís winding and the 8 ohms winding there are three small windings for inducing high frequencies.
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The 9 switches and 14 input/output outlets in this configuration offer a profusion of combinations and, obviously, this gives rise to a complicated electrical network, but in its simplest configuration (toroidal coil, lamp or resistor and a switch) even a small kid can set it up ... for safety reasons not recommended!

* An adequate power variable ballast resistor can be used with a fixed power supply.
** For more information see: The Interlaced Asymmetrical Cores Transducer.

 
       
 
Public domain.