<1) I'm using copper clad board to provide a ground plane "under" the core.
<After my last message it became obvious that this was the other half of th
<winding "through" the core.
Not required. Any whire with durrent passing through it has a field around
it. That is all that is required. More turns only reduce the current
required to attain a given field.
<2) I'm using "magnet" wire (enameled copper wire) for the core wire. I'm
<guessing it can take a couple of amps for a short period of time. I'm not
<sure that is sufficent to "switch" the #2 nut I'm using but we'll see.
The current can be quite high as those pulses will be short (microseconds).
<3) Allison referenced a waveform that looked like this:
Keep in mind that will switch the core in both directions. that was
mostly a test signal for trying materials.
<4) The diagram in the 8a manual shows the sense wires going through one se
<of cores, looping and coming back through another set. The sense wire is
<also used as the 'inhibit' wire when one wants to write a zero. This is
<done by reversing the X or Y current so that the selected cores don't get
<full write current (and thus don't switch.)
Yep the two matic selects and the sense/inhibit wire. Some planes used four
wires with the inhibit being seperate.
<5) So this is the plan:
< put three wires through the nut and wire them up as follows:
< --
< 1/h select ----------\ | | /----- GND
< 1/h select ---------------| |-------------- GND
< sense + ----------/ | | \----- sense -
For testing a "core" only two are needed. makes life simpler.
< The scope will display the current on the select lines on channel 1
< the sense lines on channel 2 (floating ground)
Good!
<6) When the current is sufficient, I should see a pulse on the sense line.
< (This is the hypothesis part, now to apply the scientific method)
Actually even if the current is low there will be a pulse coincident with
the drive pulse (transformer action). However when the core switches
the waveform will not corospond to a 1:1 transformer and also it will be
shifted in time. If the core is not suitable the signal may not be
visible.
Allison
Received on Sun Apr 25 1999 - 09:15:00 BST