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  1. CDRIVE

    Understanding the Transistor Amplifier

    Now that's much better. Now we're actually conversing! ;) Thanks for the reply. Chris
  2. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Hey Dorke, You're an absolute killjoy and sad to say (for Ross) you're also dead balls on target. Ross would be far better off working with one the myriad of RF chips and prepackaged boards available. Cheers, Chris
  3. CDRIVE

    Understanding the Transistor Amplifier

    Just to clear the air, I don't disagree about the value of Collin's website. Hell, last year I purchased his PIC Programming In ASM kit course. I thought it had value or I wouldn't have bought it. What I'd like to see change is Collin's Lone Ranger behavior. He typically rides into a thread...
  4. CDRIVE

    Understanding the Transistor Amplifier

    Uh,,..yeah. He can go there but I would strongly recommend that he first wrap his head with heavy duty duct tape.:p **************************** Collin.... You're plugging again. :rolleyes: Cheers, Chris
  5. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Yeah, that too. That capacitor network isn't loading anything. It simply forms the capacitive elements of the tank. The base input of each stage receives its signal via a low impedance (capacitve tap) to both help match the higher impedance of the driving collector or drain and the lower...
  6. CDRIVE

    Mechanical Counter - Debounce

    Yup, your switch contacts and the cap will live a long life now.;) Cheers, Chris
  7. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    I calculated L to be closer to 8uH. I can only get a result of 20uH if I factor in the varicap (~ 30pF) only. However the capacitive elements of that tank are comprised of 30pF in series with 470pf which = 28.2pF. In parallel with this result is other series connected caps 56pF & 200pF which...
  8. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Yes, my excuse for missing that little ditty is I specifically tried to avoid reading any of the psychic BS. I was laboring under the impression that the output of this thing was to a scope,.. not another human brain. ;) In the meantime I'm still waiting for Collin....:p Cheers, Chris
  9. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    I know it's not good forum practice to post consecutively but if I edited post 28 this comment may be missed. Anyway, I took the time to read some of the non psychic related data in the pdf that was posted and extracted the following: (1) A 5KΩ Pot (R?) is used for gain control for all 3...
  10. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Yeah Steve, kinda like a Tetrode. I'm sure Collin remembers them. I'm anxious to see if Collin replies to your post. Anyone want to get in on a betting pool? :D Cheers, Chris
  11. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    OK Dave, it's morning here and amazingly my head still feels like it's attached to my neck. No argument regarding chokes being used that way but if they were chokes they wouldn't be slug tuned and there would be no need for the ganged varicaps in each identical stage. Speaking of which, brings...
  12. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Yes they do use chokes wired like that but look at the 22nF Cap on the Vcc end of each coil. They effectively bring that node to RF GND which then puts the coils in parallel with the cap network feeding the next stage. The signal to the base of the next stage is picked off through a capacitive...
  13. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    I don't think so Dave. They're slug tuned and I believe resonant with the capacitive network that couples to the next stage of each amp. The other clue that incriminates itself as resonant stages is the tunable Varicap in each stage. Hey, I've been wrong before and I have killed an entire quart...
  14. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Ross, See what I mean? Think "Young Frankenstein" and Marty Feldman grabbing that pickled brain labeled "Abby Normal"! :p On a more serious note... Technology has come a long way since that article was published.... Alien influence (Martin?) some say. Anyway, there's a host of chips out there...
  15. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Hey Ross, remember that I told you we have a few psychos here? Well if you hook this thing up to Martin's head the results will look like a Star Trek episode complete with sparks, smoke, fire and Scotty bellowing that the "Shields are only at 10% and won't hold much longer"! :eek::D Chris
  16. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    The PDF calls out a wavelength of 46.2 Meters. This converts to 6489014.2424242 Hertz or 6.489MHz. http://www.unitconversion.org/unit_converter/frequency-wavelength.html From this we can now solve for "L" by plugging in the known values of "C" that form the resonant tank circuit...
  17. CDRIVE

    Psychic amplification apparatus - calculating inductance??

    Hello Ross and welcome to EP. This appears to be a three stage (Varicap Tunable) resonant amplifier. I don't think we can answer this question without knowing what the resonant (center) frequency of this amp is supposed to be. This is because some of us here at EP are a bit psycho but none of...
  18. CDRIVE

    Mechanical Counter - Debounce

    IMHO you would be wise to put a low value resistor in series with the cap only. I'm talking about ~4.7Ω. Your switch contacts will thank you for it and though lesser, so will the cap during its charge cycle. ;) Cheers, Chris
  19. CDRIVE

    Audio Through Relays

    I hope that my post didn't seem to imply that a guitar pickup outputs modulated DC because that's not what I meant to convey. For the record through, dynamic mics output AC. Electret & Carbon mics output modulated DC and only becomes AC when coupled through a capacitor or transformer. Chris
  20. CDRIVE

    Possible help programming a Picaxe 08?

    OK, this is going to be an embarrassing moment for me. My excuse is I must have had a brain fart. What I was going to reply was that a PhotoTransistor can be treated by a uC as a digital input, IE.. either ON or Off like a switch but I would have been only partially correct. In reality a...
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