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  1. CDRIVE

    5U4 Rectifier tube

    The reason I requested this information is because I think you're approach to this problem is a bit back door. You said you don't want to use a bleeder because it's wasteful. Well, I agree but there are alternatives. One alternative would be a HV Zener in series with the bleeder. If you select a...
  2. CDRIVE

    Is this true or false

    I'm afraid to ask where you garnered this glittering jewel of misinformation. Chris
  3. CDRIVE

    5U4 Rectifier tube

    What is your plate supply voltage after all tubes have warmed up? Chris Edit: Also, what's the voltage rating of the caps?
  4. CDRIVE

    Help required with placement of diodes on electromechanical vane display

    The Vcc and display lines in your image make no sense. Are they really wired like that? Chris
  5. CDRIVE

    For designing 50v,100v,150v dc power supply.

    Just a few musings about this topic: The first thought that crossed my mind was how could I employ this technology in my machine shop work. Sadly I can't think of any but at mere 10 microns displacement I don't think I'll ever be able to produce a part with tolerances that tight anyway...
  6. CDRIVE

    water level motor operator

    Raushan, did you get stuck in the space-time continuum? Your first and last post on this topic, until now, was on 09-11-2012. Glad to see that you got the flux capactitors recharged. I hear they can be tricky. :rolleyes: Chris
  7. CDRIVE

    Smart hearing aid circuit that doens't work

    I didn't catch that but on the up side this gentleman pulled the thread out of moth balls. Chris
  8. CDRIVE

    Smart hearing aid circuit that doens't work

    John, I don't disagree with anything you said. The instructor should at least let them tweak the values of the bias resistors or supply the students transistors with the identical beta that was used in the original circuit. OpAmp....YES! ;) Chris
  9. CDRIVE

    solar tracker

    To be more precise .. If IC1a's output is low a current path from the 9V rail through R4 is sinked to ground. If IC1a output is high a current path from the 9V rail through R4 is routed though R21 to the base of Q4. This turns Q4's Collector - Emitter junction on which turns on LED2. The same...
  10. CDRIVE

    Audio/LED Circuit Help

    I think this thing is being over complicated far beyond what's required to light common LEDs from the speaker outputs of an auto stereo. There's more than enough power available across the speaker lines to employ something like this. The no signal LED current is about 575uA and is set by the...
  11. CDRIVE

    Controlling the voltage into heating element

    Expensive??? http://www.mpja.com/25A-480VAC-Solid-State-Relay-UL/productinfo/17155%20RL/ Your element will pull 12.5A when fully hot. Cold will be much more. You can calculate what the cold surge current will be by measuring the resistance of the heating element. Chris
  12. CDRIVE

    Smart hearing aid circuit that doens't work

    My opinion of this design hasn't changed but if you guys insists on pursuing it you would be well advised to divorce the 555 from the audio circuit. This will only be for testing purposes. You can do this by lifting the connection to pin 3 of the 555. Then connect the + node of C3 directly to...
  13. CDRIVE

    solar tracker

    Perhaps I misunderstood your question. Are you referring to what duke describes below? If so that's why I specified that this comparator is 'Open Drain' output. IE, it can't source current. It only sinks current. Hence the need for pull-up resistors on the outputs. Chris
  14. CDRIVE

    Controlling the voltage into heating element

    While keeping the water temp within +- 0.5° would be demanding for a common thermostat, with its inherent hysteresis, this shouldn't be an insurmountable task for a uC. Whether you control the heater current with a Relay, Triac or SSR I see no need for phase slicing or PWM of the mains. Creative...
  15. CDRIVE

    solar tracker

    The LM339 is an open drain quad comparator. It operates from a single ended supply. It's common practice to indicate Vcc to only one of the comparators because the same Vcc node powers all four comparators within the same chip. The same convention applies to the ground pin. You do realize that...
  16. CDRIVE

    Smart hearing aid circuit that doens't work

    As of this post I count 4 members building this same project. Are you guys all classmates? Besides the coupling issue on the base of T2 that Duke found, there are other issues with this circuit. In my opinion this amplifier is a very poor design. There may be other issues that I've missed...
  17. CDRIVE

    led controller

    Nice work.....I think. I can't really say because, as Harald said, the pix aren't very good. Loose the phone cam! :eek: Chris
  18. CDRIVE

    solar tracker

    Does this help? Chris
  19. CDRIVE

    Is this true or false

    While it's true that Vf seems to be his singular focus there are links in his article that also address Rd. I also find it surprising that Cj and by extension switching speed seems not to be addressed. :confused: Maybe it's covered in some of those links. I did follow one of his links but it...
  20. CDRIVE

    Is this true or false

    He didn't completely ignore it,as shown here. Chris
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