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  1. chopnhack

    V-Reg Board for Breadboard use

    I salvaged a wall wart as well as the matching barrel jack from an older wireless router and wanted to make a small board to attach to my breadboard for a "benchtop" power supply until I get to that more advanced project ;-0 Should I use the 78L06 instead of the '05 if I want to make sure I...
  2. chopnhack

    Simple PWM LED Driver than randomly dims/brightens?

    Is there a simple way to construct a dimmer circuit for LED's that randomly dims and brightens without resorting to higher level digital products? I need to power three green LED's in series, preferably driven by a 9V battery. Current requirements of the LED's are 20mA with a 2-2.2Vf drop. I...
  3. chopnhack

    Why was this equation required to be in metres before resolving?

    I used Resistance = Resistivity * Length/Area, but used millimetres. Resistivity will equal P for simplicity in writing out the equations online. R=P*(5mm/pi*0.25) R=P*5mm/0.785 R=P*6.36943 1 ohm = P*6.36943 divide out the 6.36943 to get resistivity of material is 0.156999 for that size...
  4. chopnhack

    Free MIT course on Circuits and Electronics

    Having been here for a few months I have seen other folks join with interest in electronics, but with limited or no background. I wanted to share this link with you and for anyone else who is interested. It is a course as described in the title of this thread by the Massachusetts Institute of...
  5. chopnhack

    Basic Electronics kit

    For the folks on the site that have built a few items, what would you tell someone to stock who has next to no parts? Is it worth spending a few dollars to buy a series of resistors? What range of caps would you recommend? Electrolytic, ceramic, tant? All kinds? Transistors? Diodes? Zeners...
  6. chopnhack

    Hypothetical Question on Potential and Resistance

    A thought occurred to me the other day while I was reading some posts and looking over some schematics. I thought I might have understood the function of resistors in the scheme of things, but just like that, it seems to have eluded me... If we had 120v DC potential across two wires and tried...
  7. chopnhack

    USB Chargers

    Does anyone have a source for relatively inexpensive but decent quality USB chargers? Is it cheaper to make them in small scale than it is to buy them ready made? I am looking for a module that would plug into mains power and charge up to four devices. Thanks for any assistance.
  8. chopnhack

    Scrap Tinkering

    I got tired of reading theory, learning CAD programs and programming languages! I thought a little hands on tinkering would be nice for a change :-) I salvaged some LED's from a scrapped wifi board and a pcb from a kids nightlight that failed. I wanted to see if I could hook up some LED's in...
  9. chopnhack

    Isolation Transformer Potential to Earth Ground

    I am somewhat confused by the schematic below. On the isolation side of the transformer, the hot lead is shown as having a 0 V potential to earth ground? If I was to probe the hot lead to earth ground I would have no potential?? Can someone clarify this for me, I can kind of see how this could...
  10. chopnhack

    Hakko FX-888D

    I am looking to buy a soldering station. Does anyone have experience with the Hakko FX-888D? I also have the ability to buy a Weller 51 analog or digital, but I read several recent QC issues with the wellers that have lead me to look elsewhere. Can anyone recommend tips to purchase for general...
  11. chopnhack

    Bench Power Supply

    I think its time I built a bench power supply to continue my learning of electronics. I have a few thoughts of what I might need, but would like to hear other more experienced voices in this area. I am looking to build not buy a basic psu - and lets not get into the whole linear vs. switching...
  12. chopnhack

    ANSI C IDE?

    Does anyone have a source for an ANSI C compiler/IDE? I am trying to find a link, but there are an overwhelming amount of entries! I have tried several already, but they are combination C/C++. I am reading K&R's C and would like to compile some of the examples and edit them, but the C/C++ IDE's...
  13. chopnhack

    Evaluating a cap. power supply in LTSpice

    I need to run a LED as an indicator light when a switch is thrown by a irrigation control system. The switch shows 10VAC when closed. Would using a capacitor power supply be my simplest way of powering the LED off of the 10VAC? I tried to evaluate the system in question on LTSpice, but the...
  14. chopnhack

    Connectivity of plated through holes on double layer boards

    Having never worked with 2 layer boards before, what is the consensus on the connectivity of plated through holes on manufactured boards? My question is specifically related to a dip socket where I will not have room to solder the top side once the socket is installed. Do I trust the connection...
  15. chopnhack

    Hobbyist Techniques for Reflow?

    What are your techniques? With the continuing push for smaller, fewer products will be available in hand solderable packages. As a hobbyist, how are you contending with the issue? I have seen reflow done on youtube in a toaster oven! Has anyone tried using a heat gun?
  16. chopnhack

    Acrylic Lacquer for Solder Mask?

    Has anyone ever tried using acrylic lacquer spray paint like this stuff as a solder mask? I am doing a few boards in the future and sending out for pcb construction would be cost prohibitive. Thanks.
  17. chopnhack

    Help with a PIC12F1571-I/SN?

    I am looking for a model of this IC for use in Eagle. Does anyone have a resource on it? PIC12F1571-I/SN Thanks.
  18. chopnhack

    Computer Software to Simulate Circuits?

    Does anyone know of free software that can emulate circuits? I have done some research and found things like Eagle and Spice. Eagle not being free and somewhat confusing looking for a newbie, I looked at the Spice program and from what I understood it can map the output of digital i.c.'s. But is...
  19. chopnhack

    Basic question on 2 battery system and potentials between points

    I started reading "Practical Electronics for Inventors" and had some questions pop up. I checked the errata first because I got all of the other sample questions correct in determining the voltages between different points. Applying the same logic did not yield the same result as the book showed...
  20. chopnhack

    Designing a Time Delayed Relay

    Hello all, I would like to say firstly that I have limited electronics background. I can solder and read schematics to some degree and on occasion complete a print to a project. I can sometimes troubleshoot, but generally need guidance to do this with any proficiency. Now with that out of the...
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