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  1. CDRIVE

    high frequency amplifier

    For anyone interested I found it on the TI sight. http://www.ti.com/product/opa548 Direct link to spice macro model download for Tina. Zip file includes .TSM (Tina Spice Macro), .LIB (tina pspice LIBrary file), and .TLD (Tina Library Description file) http://www.ti.com/litv/zip/sbom191a
  2. CDRIVE

    high frequency amplifier

    Impressive OpAmp! Found this in the data sheet... " A SPICE macromodel is available for design analysis." It's not in the data sheet. Do you know where it can be downloaded from? Thanks, Chris Edit: Found it. See next post.
  3. CDRIVE

    simple question

    Hard to tell. We don't know what circuit this is in.
  4. CDRIVE

    Chronograph for bullets

    Use caution when using solder flux. I've used flux 'past' for many years with no issue. It looks, smells and feels just like the flux in the solder. I didn't have the same happy relationship with a clear liquid solder flux, Nasty stuff that was highly conductive.
  5. CDRIVE

    Ignatron triggering Circuit: Troublesome NPN Transistor

    This looks more analogous to RTL than TTL.
  6. CDRIVE

    high frequency amplifier

    You didn't state what output voltage (PP) you need and what the waveform will be, Sin, Square, Triangle ? Does the signal have go negative?
  7. CDRIVE

    Need some help to smooth a PWM signal, to stop resonance in motor.

    Apples, I watched your video and the Diamond plate caught my eye. Did you fabricate that housing?
  8. CDRIVE

    H-bridge with TIP 122/127

    Electronics Point has a tool bar. Scroll up to the top of the page and click on the "Tutorials" button and start reading. It's a structured electronics course.
  9. CDRIVE

    MOSFET IRF540A circuit.

    Justin, whenever I found time I came back to this project but I must tell you that the biggest problem is when your battery drains down very low. A regulated Vdd must be supplied to the Axe and voltage regulator require a min input voltage. I can't help but think that you have a very simple...
  10. CDRIVE

    H-bridge with TIP 122/127

    These are plots of Common Emitter and Common Collector amplifiers being used as switches. Note that I intentionally made the source voltage (VS1) only 1.0V because it will give you a much better idea of how these two configurations will respond to a small control voltage. This is called a...
  11. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    Too bad that all split phase motors don't have access to the CS like this one. It took me more time to remove it from my drill press than to access the switch. It only required removing an end cap that is nothing more than a cover plate. I had just finished replacing a 120V motor on my...
  12. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    Yes I am. I said it and I was dead wrong. It's not the first time and I doubt that it will be the last. :D Did you know that Crow is rather chewy? :rolleyes: So, the question remains .. The engineer friend drew the CS as a SPDT, that switches either the Start or the Run Cap in. Do you think...
  13. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    John, I found a number of diagrams with the design you describe. For certain.. it's painful but as I said, I will gracefully concede. Consider it done. ;) Chris
  14. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    John, please post a link with the design you describe. I've never seen one and the design makes no sense to me. That said we all make mistakes and if I've made one I'll gracefully concede to it. So, as they say in Missouri.... :D Chris BTW, the caps aren't used for impedance matching...
  15. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    Start windings draw 2 to 3 times the run current. They're never left in the circuit because they are intended for intermittent duty only. They will fry in short order if not disconnected quickly. I will not argue that his friend got the motor going but I don't believe the schematic he drew is...
  16. CDRIVE

    Help Me/ hook up a forward-stop-reverse motor cont switch on a 220volt mill machine

    Why not disassemble the motor and see if you can fix the start switch. It should be closed at rest. Maybe you lost a spring or the contacts need to be cleaned and resurfaced. The CS is a simple assembly and usually requires removing only one end bell.. 'four nuts'.
  17. CDRIVE

    H-bridge with TIP 122/127

    Actually those plots don't demonstrate the same transistor being used as a switch or and amplifier. They're plots of base current and voltage vs output current and voltage. On the other hand the plots do demonstrate how the common emitter collector current suddenly snaps on as compared to a...
  18. CDRIVE

    555 timer reverse polarity circuit

    welshdragon, I don't know if having the LEDs being powered by your current source is that important to you but if it is the LED's can be put in series with the output pin of the relay or in the + & - legs of the supply. The LEDs would have to be shunted with an appropriate value resistors...
  19. CDRIVE

    555 timer reverse polarity circuit

    No, I couldn't. I dismissed connecting the LEDs to the Output because he's maintaining constant current through his load. Yes, this means that his +- supply can't maintain a constant 30V but this isn't important to him, the current is. ;)
  20. CDRIVE

    configuring hardware key with pc

    Actually, I was going in a plug and play (mouse click circuit) direction, which is why I asked this. You're OptoCoupler would still be used. On the other hand keyboards are dirt cheap, so I guess tapping into the Enter key is no biggy. Chris
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