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I am trying to make my own core rope rom, according to the link. I have 15mm ferrite cores, which I wound about 30 times with 1mm magnet wire. I thread the primary ( also 1mm wire) through one of the cores (once) to test it. That was connected to a diy dc pulse generator based around the 555 timer, which is fed 9v. When I first tested it, I barely got any voltage from the secondary, about 1mv according to my multimeter set to dc (my ac 200v range which is the lowest picks up nothing). I also tried connecting a low power led, which did not light up. I figured the dc was not being pulsed at a high enough frequency (7.5hz ish) so I changed the circuit for the dc pulser so that it puts out at about 45hz. However, I’m still having the exact same problem. Can anyone think of anything i might be doing wrong? At this point, I’m assuming i am not using the correct frequency. If so, is there a way I can calculate this? Any help would be much appreciated.

http://qrp.gr/coreROM/

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    \$\begingroup\$ Perhaps see if you can use a computer sound card like a low performance scope. \$\endgroup\$ – Chris Stratton Feb 24 '19 at 5:43
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    \$\begingroup\$ as @ChrisStratton said, connect the wire to the microphone input of your computer .... download Audacity for recording and displaying the pulses .... audacityteam.org \$\endgroup\$ – jsotola Feb 24 '19 at 5:51
  • \$\begingroup\$ Okay thanks. If the pulses are so brief, how can I use them to light up leds when the transformer has current flowing through the primary? \$\endgroup\$ – Steve Feb 24 '19 at 7:51
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    \$\begingroup\$ Seems like you need to spend some more time studying the implementation of the historic technology you are trying to replicate. EESE is for specific questions, not "how to"'s. \$\endgroup\$ – Chris Stratton Feb 24 '19 at 8:19
  • \$\begingroup\$ It’s not a how to question. After weeks of work, studying and troubleshooting the core rope memory, I can still not find the problem, which is why I came here, asking SPECIFICALLY if anyone could think of any reason that. I’m not sure how my question came off as how to- I provided information on the setup, and even referenced the how to which used. \$\endgroup\$ – Steve Feb 24 '19 at 8:41
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the pulse will be very brief, if you have't got some sort of oscilloscope it will be hard to observe. Perhaps use it to trigger some sort of flip-flop, or flash a high-brigtness LED.

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I do not remember the type of clock I used in this one, I think it was a square pulse generator and it was made using a simple 555 timer. Think of the circuit as transformers. Transformers work only on AC or on rising and falling edge of the square waveform. at the rising edge input, you get voltage at the output. at the falling edge input, you get reverse voltage at the output. The working principle of the ROM is very simple, it is not based on square loop cores, so any transformer can be used. The turns ratio was big, so that I can get big voltage at the output. The current out of the 555 was enough to light up the leds.

The cores used are of the 37 mix, so they work fine up to HF. But ANY core will do because you will drive it at KHz only. Just make sure the generator has enough current to provide, I am not sure if the soundcard output will work at all!

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  • \$\begingroup\$ This is random commentary, not an answer. \$\endgroup\$ – Chris Stratton Oct 19 '19 at 18:50

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