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  1. CDRIVE

    Motor control diy

    Kris, nice job on the schematic. MasterArcher hasn't commented on it though. Perhaps you were spot on about keeping it simple. I hope we don't have to defibrillate him! :D Chris
  2. CDRIVE

    PWM Online Battery Charger

    Unfortunately the information in the link isn't useful. I asked for the schematic because I wanted to be sure that if mains power was lost the battery wouldn't back feed into the supply. That's what the Diode earlier in the thread was all about. I think it was ElectroBrains that posted it.
  3. CDRIVE

    Valve (tube) amplifier schematic help

    Yes, my post was exemplary of anal retentive discourse. :D Chris
  4. CDRIVE

    VHF booster

    Miguel, I'm heading out to my watering hole. In the interim here's some good reading for you. Google is your friend. Do some leg work while I'm kick'n back...
  5. CDRIVE

    Valve (tube) amplifier schematic help

    Kris, initially my reaction to this was "Exactly!". In fact I drifted off to another thread but the more I thought about it the more that little voice kept saying "Well, not exactly". While it may seem true that the only time DC input power Vs Signal output power plays a role is in power...
  6. CDRIVE

    VHF booster

    Dave, I don't want to hijack his topic so go here...https://www.electronicspoint.com/lets-hope-its-just-bad-tuck-t251707.html#post1489049 Chris
  7. CDRIVE

    Let's Hope It's Just Bad Tuck!

    Dave just posted to a thread https://www.electronicspoint.com/vhf-booster-t251559p3.html#post1489009 that he was hospitalized but didn't say why. Lets hope he tells us here that he's recovering. Get well Dave. Chris
  8. CDRIVE

    PWM Online Battery Charger

    Do you have a schematic of your switch mode regulated supply? If so please post it.
  9. CDRIVE

    Valve (tube) amplifier schematic help

    Solidus, got that? It's not related to efficiency. Power efficiency is the ratio of DC input power to the pate vs audio (signal) output power picked off at the plate. The heater is not relevant to this parameter. Amateur radio operators should or did know this well. This is because the FCC...
  10. CDRIVE

    PWM Online Battery Charger

    Here's the same circuit that I posted earlier but with an automotive lamp wired in series with the battery. The addition of a lamp makes it impossible to overtax your power supply. As you can see in the plot I started the simulation with the battery fully discharged at 0 V. The lamp prevents...
  11. CDRIVE

    PWM Online Battery Charger

    Neither. Lead Acid and Gel Gells have little in common with Ni-CAD's Ni-MH or Lithiums. Out of the three Lithiums are the least finicky though. Are you desirous of complicating this? :rolleyes:
  12. CDRIVE

    VHF booster

    Give me some time to see what I can work up. Typically, I like to Spice a circuit before I post it but I may not be able to do that with this transistor.
  13. CDRIVE

    Bicycle Turn Signal Electronics needed.

    I think I could be very happy there but I'd rather be the guard in the wine cellar. :D
  14. CDRIVE

    VHF booster

    OK, I believe it should read like the following: Vceo Max: 12V Vcbo Max: 12V Vebo Max: 2V Pd Max: 150mW Ic Max: 50mA hFE: Min 30 Max 180 fT: 300MHz ( Where gain = unity) Is this an NPN and do you know the noise figure? Chris
  15. CDRIVE

    PWM Online Battery Charger

    I've attached a schematic and a DC Transfer Curve Plot that addresses your question. The current curve displayed are Dependant on the internal resistances of the Battery and the PSU. I chose a ballpark value for these as shown on the schematic. They can be a good deal lower than this depending...
  16. CDRIVE

    PWM Online Battery Charger

    Basically the main difference between a power supply and a battery charger is the absence of filter capacitors, which aren't normally needed or found in chargers. A DC power supply can do dual duty as either but an unfiltered charger can't serve as a DC power supply because they output pulsating...
  17. CDRIVE

    VHF booster

    Post what data you have. Let's see what we can do with it. How many of them do you have? Curious,.. Are you trying to receive channel 7 in Miami?
  18. CDRIVE

    Motor control diy

    You mean to say that man didn't steal this technology from extra terrestrial Aliens???? :rolleyes: Have fun with the design!
  19. CDRIVE

    Electromagnet Battery

    Are you familiar with Ohms Law? Your coil resistance to produce 1.25A @ n voltage will be the same as a resistor. Your coil resistance will be relative to the wire guage and wire length. That said, I haven't done any electromagnet winding since 1959. Fortunately we have members that have more...
  20. CDRIVE

    Valve (tube) amplifier schematic help

    Higher voltage "Gain" does not translate to higher power output or PSU current drain. The only thing that draws significant current (Power = E * I) in any of these tubes is the filaments. A little 9V battery could power the plate circuits for months.
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