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    MOSFET 12VDC Relay?

    Woops. Trying to "replace" traditional relays. Right, the IFR520's 270milliohm causes a comparatively higher voltage drop than other MOSFETS. I've been looking over datasheets. Some are in the area of 12 milliohm. I agree that every relay has a power cost. I'm looking for recommendations on...
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    MOSFET 12VDC Relay?

    I'm trying to traditional relays with something more modern and efficient. The signal voltage is 12VDC. The design load is 12VDC/10A. Efficiency is a big priority. I see there are a bunch of inexpensive pre-made "arduino" type MOSFET driver modules which would work for this application...
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    TRIAC Heat Generation & Dissipation

    Harold, Thank you for the thorough reply, and for clarifying that the switching is in fact not the primary source of the generated heat. A 150mm * 60mm * 60mm, 24-fin aluminium heat sink has been ordered. Per a calculator found online, this heat sink should provide a thermal resistance of...
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    TRIAC Heat Generation & Dissipation

    Hello all, I am putting together a TRIAC power controller that will control a 4500-watt electric heater: ~18.75A@240VAC. The TRIACs I am considering for this circuit are 40-amp TRIACS: NTE56028 in TO-220: http://www.nteinc.com/specs/56000to56099/pdf/nte56028.pdf NTE5679 in TO-3...
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    Permanent Magnet DC (PMDC) Motor Controller

    adamq submitted a new Showcase Item: Permanent Magnet DC (PMDC) Motor Controller Read more about this showcase item here...
  6. Permanent Magnet DC (PMDC) Motor Controller

    Permanent Magnet DC (PMDC) Motor Controller

    I assembled a PMDC (permanent magnet DC) Motor Controller for use with my variable speed mini lathe. Forum member "Minder" was extremely helpful with this. Although it's a simple circuit, it can still be confusing for those of us who aren't very experienced with building electronics. The motor...
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    SCR Motor Controller

    You're right. Which made me realize it has to be something I did. And it was. I forgot to attach the negative side of the capacitors to the negative bus. Stupid. :) Minder, thank you so very much. You are the only reason I got this working! Learned a lot about DIACs, TRIACs and some more...
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    SCR Motor Controller

    Happy to report it is working with the NTE diac... However the speed control is ineffective with the 250k pot. I tried a 4.7M resistor for fun and it's probably still 3/4 speed or better (I jump the resistor to compare). Any pot value recommendation? Or advice on how to size the pot? Edit: it...
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    Identifying an individual to a system - Ardiuno

    Jailbreak the phone :)
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    Raspberry Pi zero with camera

    Yes it's compatible if your pi zero has the camera connector on the end. It's a finer connection than on the full size raspberry pi, though, and you need the adapter ribbon cable.
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    Identifying an individual to a system - Ardiuno

    Does the iPhone have NFC? I'm not familiar with the different models
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    SCR Motor Controller

    OK. I'll pick up a DIAC somewhere before i power it up then. Thanks Minder. Looks like a shop around here has an NTE6408 which is a DB3 equivalent..
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    Identifying an individual to a system - Ardiuno

    I was thinking a keyfob also, except he doesnt want to do RFID... Too bad, you could use an existing fob, even.
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    Identifying an individual to a system - Ardiuno

    Does it have to be wireless, and arduino? I'm not very familiar with arduino, but if you use an old model A rpi, you have the GPIO for the buttons/relays/whatever, and if you connect the phone via USB, you can get device info that way (specifically serial number), say from lsusb.... It might be...
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    SCR Motor Controller

    OK. It's assembled. Before I go ahead and fire it up, I'm hoping you guys can look it over and give some advice. Save some smoke, just maybe :) I'm still not sure about that signal diode vs a DIAC. Attached are the labeled pic with connections in blue, and without labels, and the original...
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    SCR Motor Controller

    HT-32 was unavailable. Clerk recommended 1n914b in its place. Datasheet describes it as a small signal diode, not a DIAC. https://www.fairchildsemi.com/datasheets/1N/1N914.pdf Thoughts?
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    SCR Motor Controller

    Speaking of buying a pot, is there a reason I couldn't salvage the pot that is on the lathe already? It is a 4.7k pot. Ohms out fine.
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    SCR Motor Controller

    Linear pot. Thanks. Otherwise a logarithmic pot would exponentially increase/decrease, making it hard to control?
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    SCR Motor Controller

    One more thing actually. I don't understand the motor inside the diodes. Is it just drawn this way? My plan was to go ac > 8a rectifier bridge > switching components > motor...the reason being I could use a dpdt switch to reverse polarity and direction The schematic uses 4 diodes to rectify...
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    SCR Motor Controller

    Excellent minder, thank you. Indeed there is a choke present on the old board, must be why. Off to the parts store to buy three of everything :P
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