Larry's Blog

FERROMAGNETIC CORE MEMORY

Here is a picture of setup for experimenting with Ferromagnetic Core Memory.

On the left you will see a composition electronic card containing ferrite cores
which have been cemented right in the card. I have removed all the original wires from it. The next circuit to the right of it is a latching circuit with an LED which is designed to latch a signal coming in on the sense wire. There is other circuitry for the WRITE signal which magnetizes the core in one or the other polarity.

My purpose in doing these experiments is not for any practical reason such as using the core memory for data storage. Computer memory storage is already very much available today. But I wish to implement all the steps that are used in reading and writing this kind of memory. I have already a long list of terms and phenomena that are connected with magnetism in general, and ferrite cores in particular.

Hysteresis loop, domains, permeability, saturation, flux density, residual magnetism. A few years back, I was excited to learn that magnetism lies within the electromagnetic force, and actually stems from the spin of electrons in atoms, in very small areas called domains. In certain materials, the electrons can be forced to have the same spin, and this produces the magnetic force.

I am really excited in this new study and want to learn all about it. I might mention here coincident current, which is used to write to a particular core in a memory, by sending part of magnetizing current on one wire and part of it on another. Only where the 2 currents cross, is the threshold reached which is adequate to flip the core to the desired polarity.

Any way, there will be more!