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  • Users: LucasBS
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  1. LucasBS

    Help on a darlington

    Despite the risk of being cast back to school, I'll ask help on this dimmer circuit for a LED strip I have: - MJE13003 - http://www.onsemi.com/pub/Collateral/MJE13003-D.PDF - 2N3904 - https://www.onsemi.com/pub/Collateral/2N3903-D.PDF - 1k and 10k pots available - Many resistors This MJE...
  2. LucasBS

    Help designing a dimmer

    I need to design a dimmer, but I'm having a problem with the potentiometer, that heats up too much It's 150k, and it's practically impossible to get a different one The same problem goes to the diac/zeners: also difficult to get a different one. Right now I'm using the DB3 diac, that conducts...
  3. LucasBS

    Capacitor only filter for a twitter

    I need to make a High pass filter for a twitter (allowing 1kHz or more) I thought about putting a capacitor in series, but been reading that it needs a resistor too None of the answers have convinced me of why Plus, a resistor across (?after or before the capacitor?) will (?) reduce the...
  4. LucasBS

    Basic channel selector request

    I'd like to toggle between two sources of stereo audio (each having L, R and Neutral). Who can help ? I'd also like to do that using one of those basic bistable on/off switches (https://i.stack.imgur.com/N0LfN.gif) - And more important, if possible: basic components only. No extra ICs apart...
  5. LucasBS

    Roll bending forces

    I need to calculate the forces involved on a roll bending machine and components. I could find no documents or books on this regard Any recommendation ? The product is a 5mm thickness steel wheel, to be formed on a single roll (male and female, profiled to the final form), gradually pushing...
  6. LucasBS

    How can this supply work

    Here's a schematic: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQHGkfHrtyQK9mTr5stnyC-Occsj3gSU2OLPVISGzxgmgdWiigYeCITiYIM It's a very popular power supply But I wonder: how can a PNP transistor conduct if the voltage at the emitter is the same as the base One could argue that the...
  7. LucasBS

    Switching Vs. Zener controlled supply

    What are the pros an cons of a Switching mode power supply Vs. a zener controlled power supply (also known as emitter follower voltage regulator) ? Everyone knows the first one. Here's a picture of the second one...
  8. LucasBS

    Working with the MCR100-8 thyristor

    I'm trying to make a phase control-like dimmer with this thyristor (I've attached a schematic candidate) Maybe I'm reading the datasheet* wrongly, but I see many hard-to-swallow values, like 0.8V for the MAXIMUM gate voltage, and 300uA (MICRO AMPERES) for the current To achieve a low output...
  9. LucasBS

    Choosing the right diode for a given function

    When making a bridge, it's obvious that I have to choose a diode based on their current and voltage ratings. But for other functions, like Logic Safety Switching Etc What is a germanium diode for ? Shottky barrier ? How do I choose a diode to put next to a relay, and why ? When exactly do I...
  10. LucasBS

    Join two bridges by a common ground

    Please view the uploaded picture. There are three GND on the schematic, two of them belonging to a bridge rectifier with different power handling. I would like to join all of them without making a firework Is it possible ? If I don't join them I don't know how to make the switching transistor...
  11. LucasBS

    Maximum capacitor current

    I want to put a capacitor on 127 AC, so that it's inductive reactance can lower the current. How much current can a typicial polyester 400V rated withstand under this condition ? I need around half ampere
  12. LucasBS

    Maximum gate voltage on a triac

    I have a TIC226D triac. I see maximum gate current on it's datasheet (50mA, if I'm not mistaken), but I need to know the maximum allowed tension. Is there a way ?
  13. LucasBS

    What am I doing wrong with this PSpice design

    Look at the picture https://www.dropbox.com/s/aju24pifejxsyxx/PSPICE1.png I cannot put a simple Source+resistor to work Parts are filtered to containing PSpice simulation Source: Vac 2x Analog: R Default Grounding Tried changing the values of the source to 1000V, 1000Vac, etc... Nothing
  14. LucasBS

    Infinite construction line on inventor 2013

    How to make an infinite construction line on inventor 2013 ? New on this business here Nothing found on google Autodesk help is useless... Line tool has no dropdown with other options. Miracle anyone ?
  15. LucasBS

    Creo 2 - Problem with Swept Blend

    Trying to use the Swept Blend tool to bind those two areas marked in gay colors (Binding a square sketch and a circle sketch), but seems like Creo is trying to connect the opposed face of the square area... something like that... I had to Add two Blend Vertex In 3ds max, for those who know it...
  16. LucasBS

    Fixed working directory

    I've searched, but none with this same problem. The startup directory is never the one I'd set in the previous session. "Start in" is set to "D:\Documents\", but PROE ignores it and goes to "C:\Windows\System32\" 'file_open_default_folder' IS 'working_directory' ????
  17. LucasBS

    Help on modeling a car part with surfaces

    How do I model that part (attatchment) using pro/e 5 ? Preferentially, using surface methods (which you would have to teach me). The focus really IS learning 3D surfaces. Some parts have very precise measures, like corners and the radius of the detail on top. Others are soft and free. I guess...
  18. LucasBS

    Scale object in Pro/engineer ->drawing<-

    I have a .part on this program. Imported it to a new Drawing, for A4 size. But the object is too small on the sheet... Won't occupy a third of the availiable area.. it's hard to see, and a waste of space. How do I scale the object inside the Drawing for it to look bigger without losing the...
  19. LucasBS

    Load back appearance

    Please, teach a noob. Tell me why always I load a .prt, the materials I assigned to that, on another session, won't come back along? Thx forward.
  20. LucasBS

    Fatal crash

    Hi. Seems like I'm the only one with this error. Had to create this account here just for that problem. PROE WF4 F000 It begins in the installation, around the third page, where you select which features you want to install: By default, Mechanica is not marked, and if I try to mark it, the...

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