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  1. Fish4Fun

    Downconverter Mixer Design

    Chunx, Welcome to the forum! RF is REALLY not in my wheelhouse, I am sure others will be able to help, but "off-the-cuff", I thought AM stood for "Amplitude Modulation" while FM stood for "Frequency Modulation".....I have never done more than take a precursory look @ RF in general, and the...
  2. Fish4Fun

    IR2110 Mosfet Driver Capacitance Question

    I have just assembled 3 * IR2110 Hi/Lo Side Drivers onto a PCB I mocked up to do some BLDC motor tests...for the High-Side Floating Supply I have 1 * 0.1uF Ceramic, 5 * 4.7uF Ceramic and 1 * 68uF electrolytic (obviously in parallel)...I realize 6 Ceramic Caps are over kill but I wanted to make...
  3. Fish4Fun

    Virtins DSO-2820 PC-scope, is it any good, and OK to buy?

    sverk, I have long thought a "PC Scope" a cool idea, and they have come a long way in the last decade or so....that being said, I have never used one. When faced with buying a new scope I keep ending up getting "free standing" scopes. There are 2ch import offerings starting @ ~ $400, and some...
  4. Fish4Fun

    laser ablation of PCB resist

    Yes, if those boys and girls in England could just catch up with Jennifer Lewis in Chicago my life would be a lot easier....http://www.matse.illinois.edu/faculty/Lewis.html I have been following her work for a while, "conductive inks" are all the rage on the unlimited budget side of...
  5. Fish4Fun

    laser ablation of PCB resist

    *steve* Thanks for the Link! I "joined" their forum and posted a newbie question about the suitability of a Laser Diode for paint ablation....we will see what kind of response a 1 post newbie receives ;-) While I know almost zero about lasers, I do have a pretty good handle on driving...
  6. Fish4Fun

    Half Bridge Converter Question

    @Kris and Adam...Great read, but I think the elephant in the room is that the OP wants to design//build a "high power SMPS" w/o a good working knowledge of existing bridge topologies/methods/designs. "High power" SMPS implies one that is line driven and likely > 500W; I think the more prudent...
  7. Fish4Fun

    Electric motor

    jerryb, @12Vac supply, Yes and No: Yes....IF you use a rectifier and a voltage regulator (likely 3V to 6V depending on the servo). NO....If you attempt to connect the 12Vac directly to a DC servo. @Suggestions...I like the servo idea, I see lots of reasons it might be a good choice. Another...
  8. Fish4Fun

    need a "translator" for 12 VDC power supply project

    madbear, Welcome to the forum! You are going to have a difficult time building a 15A current regulator, this is NOT a trivial project. An LM317 is simply not going to work for you. Anodizing aluminum is certainly best done with regulated current, but you aren't going to require "ultra-fine"...
  9. Fish4Fun

    Motor Starter Stage Simple Circuit

    jwalton1, Welcome to the forum! First: Line powered 2.3kW speed controls are NOT: 1) Cheap 2) Easy 3) Good DIY projects. Things to consider: 1) 230Vac is an RMS value so the DC voltage after being rectified will be ~325Vdc. 2) Any passive means of dropping 325Vdc to 180Vdc @ 10A will...
  10. Fish4Fun

    laser ablation of PCB resist

    *steve* I wish I had access to a CNC laser! I direct mill a lot of prototype//one-off PCBs on my little desktop CNC router...but there are caveats to the layouts...SOIC is about as fine as I attempt....I haven't found a good way to automate gcode generation....obviously I can import image...
  11. Fish4Fun

    JBOD Wish Device

    So we all have some media files we like to play on various devices and at some point we all have to consider storage space, convenience, power consumption, cost and data integrity...personally my current solution is a 7-Bay linux based NAS configured in RAID6 (RAID5 with an extra parity disk)...
  12. Fish4Fun

    Set longer sampling time of ADC of TM4C123GH6PGET

    forever074, The "sample time" is part of the hardware definition of the ADC, asking how to change the sample time is like asking how to change the output voltage of an LM7805 voltage regulator...it isn't an option....Perhaps a firmware solution would be a better approach...take 16 consecutive...
  13. Fish4Fun

    A new type of BLDC motor drive?

    eem2am, This is a bit out of my wheelhouse, and you obviously have a great deal more experience in motor-drive design than I do, so if this is too far off-topic, please just ignore it. In CNC servo drives "constant current mode" is the most common mode of operation...as the RPM varies with...
  14. Fish4Fun

    IR Project - Viewsonic Monitor drives IR module nuts

    Hrmmm, form your description it would seem that the "noise" is coming from the monitor's light output and NOT more traditional EMI....This would suggest one of two things: 1) The monitor is putting out light in the IR range, 2) The Monitor is putting out pulses of light near the carrier...
  15. Fish4Fun

    'Low Power VLSI' :Help me to choose best domain for M.tech project

    gstekboy, Welcome to the forum! Guess no one else is going to bite, so.... VLSI ("Very Large Scale Integration") is a somewhat qualitative descriptor....in historical context it could mean anything from a 74xx Logic chip to Intel's bleeding edge multi-core processor family....Likewise, "low...
  16. Fish4Fun

    Changing a motor's direction each time power is supplied

    Stew, Welcome to the forum! I understand what you want to do, but there are a few questions that need to be addressed before anything more general that "wire it like a two switch light circuit" can be given as an answer.... 1) At what level do you want to implement the control: a) In the...
  17. Fish4Fun

    Increasing Line 120VAC to 340VDC

    Your MATH is correct, your equations are NOT representing what you want. First Watt-Second (ws) is a measure of power over time and is equivalent to Joules, similar to the kWh used on your power/hydro bill NOT Power per Unit of Time. @ Any Rate 1 Watt = 1J/1Sec. 1ws = 1j/s * 1s = 1J. So...
  18. Fish4Fun

    Increasing Line 120VAC to 340VDC

    @-->Steve, Not arguing anything about flash duration, I simply picked 1mS as a calculation point. Your link suggests that 1mS is roughly 1/3 their "longest flash period" which (appears from the graphs) to be ~3mS (and in the literature 3.33mS). This does not fundamentally change my...
  19. Fish4Fun

    Help with Dallas 1-wire circuit

    makidoja. I cannot imagine the scenario where one would WANT to use something other than the specified voltage range of 3.0Vdc to 5.5Vdc, you absolutely have to have a microcontroller to communicate with the device family, and I cannot think of any situation where one would have a...
  20. Fish4Fun

    Help on circuit

    Oh, and you are right to raise those questions, and the answer is, "Its a trade-off": Risk of Catastrophic Failure for Circuit Simplicity. The OP has a variable number of 1W & 3W (350mA, 750mA) LEDs and the PWM adjustable design current is limited to < 200mA/400mA by firmware. There is no...
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