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  1. hevans1944

    TDA2030a Amplifier I.C. Specs

    Foot note #1 to Table 7. Recommended values of components for a typical amplifier says The value of closed loop gain must be higher than 24 dB. And did anyone notice that the background "watermark" on each page of the datasheet warns that this product is obsolete? It (or its "clones") seems to...
  2. hevans1944

    Value of this crystal?

    There are a couple of possibilities to also consider. Is this the correct key fob for the vehicle it is intended to be used with? In other words, was it correctly synched with the receiver in the vehicle initially? Is there a good battery in the key fob, or did it die without warning? These key...
  3. hevans1944

    Value of this crystal?

    @davenn, @73's de Edd: Thanks, guys. I guess the "giveaway" was the OP's statement that it belonged to a car key. I must be getting lazy for at least not trying to Google that. And, Yikes! Forgetting about the 433 MHz ISM band... I hope the FCC doesn't use that against me and cancel my Amateur...
  4. hevans1944

    Tesla Coil Kit - help needed

    Here is a web site you should visit for more information on DIY (Do It Yourself) Tesla coil construction. There is also a Tesla Coil Web Ring that links such sites together. The components in your video are just part of what you need to construct a working Tesla coil, but they are the most...
  5. hevans1944

    Value of this crystal?

    So, whuts going on at 433.920 MHz? And how in the heck did you find this, @bertus?
  6. hevans1944

    What are these sections of this power supply?

    I suppose I need to develop calluses on my left finger tips to properly press the strings against the frets. And I reckon a 4x12 stack means four 12-inch speakers in a cabinet (cab?) driven to perhaps thirty to fifty watts by a vacuum tube power amplifier? I do love "the science of loud,"...
  7. hevans1944

    What are these sections of this power supply?

    Years ago I bought a Conn organ off the showroom floor, probably paying waaay more than it was worth. I think it was a Conn Model 552 Theatrette Organ. See images below. I installed it in our smallish living room and (probably) proceeded to annoy the neighbors as well as my family with my feeble...
  8. hevans1944

    Nichrome wire heat up

    I have never had much success cutting either open-cell or closed-cell Styrofoam or any other kind of "foamed" plastic, probably because I lacked the patience to find the right temperature for the nichrome cutting wire. My fallback position was to use a really sharp knife, which is clumsy and...
  9. hevans1944

    Nichrome wire heat up

    Nichrome, a nickle-chrome alloy, is typically used as an incandescent (red hot) heater element in electric ranges and small home appliances such as toasters. It has the nifty property of not "burning up" when heated in air. At lower temperatures, nichrome wire is used to cleanly cut styrofoam...
  10. hevans1944

    What are these sections of this power supply?

    I love the "sound" tube amps are capable of producing, but that seems to have been all but forgotten by solid-state designs, both analog and digital. Of course tubes never really died, and the old circuits became classics that are now carried on by a new generation of builders. So what if the...
  11. hevans1944

    What are these sections of this power supply?

    Yeah, I know what the simulation is for. As you probably know, there is a huge difference between seeing an audio response curve and actually hearing the difference. I guess a parametirc EQ might work, but each point would need to be entered manually. Not a really quick method for evaluating...
  12. hevans1944

    trying to understand amp limits? (10 vs 15 vs 16A)

    What other information do you seek? I didn't see a question in your post.
  13. hevans1944

    Searching for small load cell or method for measuring forces in the 1 g (10mN) range

    Most load cells, at least the ones that I am familiar with, use strain gauges in an electrical Wheatstone bridge configuration to measure the minute compression or extension of a stiff "I-beam" shaped material when a longitudinal force is applied along the long axis of the beam. This type of...
  14. hevans1944

    What are these sections of this power supply?

    I downloaded the app and found that it works just fine in Windows 10. Now, all I need is some way to link it between the microphone input and the sound card output of my laptop so I can actually hear what the different tone control stacks actually DO to guitar string sounds. We have three...
  15. hevans1944

    Coronavirus transmission prevention device.

    I somehow lost track of time while cooking dinner for me and my wife yesterday, and so forgot to attend the March meeting of the Tamiami Amateur Radio Club (TARC). Then I opened an e-mail from the president of the club saying the meeting WOULD NOT be canceled because of any threat from the...
  16. hevans1944

    Coronavirus transmission prevention device.

    I am still trying to find paying work that I can do from at home. I was "retired" from my last job at the end of December 2014, at age 70. My manager said there was no more particle accelerator work, which was may have been true, but I had been building electronics instrumentation for the...
  17. hevans1944

    AC power from solar installation into home wiring?

    As a "rule of thumb" solar insolation is about one kilowatt per square meter. An efficient solar panel can extract at the most about 15% of that, say, about 150W/m2. You would be lucky to be able to carry in a van, and present it to the Sun, as much as two square meters of solar panels providing...
  18. hevans1944

    Coronavirus transmission prevention device.

    I have only "as much time to kill" as I have time left to live, but I seldom worry about how much that is or how best to use it. Posting here is one of the few vices left that I can still afford, but there are always other things to do... even (or especially) in retirement. Maybe more so in...
  19. hevans1944

    Problem with inductive load

    Is THIS what we are trying to drive with the Xmega CPU? Are you overthinking this? WIll the XMega output drive the servo dirctly, as @Harald Kapp suggested in post #2, his comment issue #4?
  20. hevans1944

    Found problem in Kenwood KR-V95R

    Okay, welcome to the gray-bearded old farts club.:D Clean-shaven old farts welcome too. It would have helped if I had known that history up front. I almost never try to teach old folks how to suck eggs. Still, it looks like your approach works and it probably saves a ton of time and money...
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