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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 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 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 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 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 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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