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    Checking a capacitor

    You can test electrolytics with the ohm meter on the 2M scale. Just multiply the 2MX the capacitance and it will give you the time in seconds for it to charge to 63% Example: 2MX10uf=20sec. But like Steve said, it could still be bad. If you don't have an esr meter, you can apply like a 100KHZ...
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    Modifying fluctuating DC voltage

    Ok, a 16KHZ freq. has a period of 0.624m seconds. You need to have a monostable oscillator set to 0.625msec. A 625ohm resistor should do that. Hook it to pin 7 and 6 and your .1 cap. to ground. Hook the output of your op amp oscillator to the trigger. Hook a 100k pot to V+ and to ground, with...
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    Modifying fluctuating DC voltage

    You have that 555 set up as an astable oscillator running a a very high freq. Unless you have a hefty op amp it will not be able to sink the voltage on the control. If I remember right, the control puts out over 100ma. The only thing you are going to do is vary the freq. If you would explain...
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    pwm to control a dc motor

    A npn transistor has to have a positive voltage on the base and a negative voltage on the emitter in order to be on. What will happen if the emitter voltage goes up but the base voltage stays the same? This is called negative feedback because it is out of phase with respect to the base. You know...
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    pwm to control a dc motor

    An emitter resistor is used to prevent thermal runaway. The more current thru the resistor, the more voltage is across it, which is negative feedback to the base. The hotter a bipolar transistor gets, the more current it passes, until it shorts or burns out. It is usually a low value. I have...
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    DIACs gone the way of dinosaur?

    I was looking at diodes in wikipedia. It looks like it says that diodes over 5.6 volts are avalanche diodes. But it is not really clear. ha :) Well, I just went to the Jameco website, and they say nothing about the higher voltage zeners being avalanche diodes. I also found that they do...
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    DIACs gone the way of dinosaur?

    I built a simple lite dimmer circuit and I accidental shorted out my diac, so I replaced it with two zeners. Don't know how long it would have lasted but it worked good for testing my circuit. I was trying to vary the current dynamically, but I couldn't get it figured out. I think I have thought...
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    Want to build ESR Tester

    I want to build one too. I hope you let us know how your circuit works when you build it. Here is another circuit, that I was thinking of building. http://electronics-diy.com/esr-meter.php
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    DIACs gone the way of dinosaur?

    Maybe I'm wrong; I only know that I replaced one with zener diodes and the circuit preformed exactly like it did with the diac. Have you ever tested one, to see if wikipedia is correct?
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    DIACs gone the way of dinosaur?

    A diac is nothing more than two zener diodes back to back. I have used two 34 volt zener diodes before and they worked good. I don't know what the exact voltage of a diac is. :)
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    Time Varrying sources in Orcad

    You can vary the frequency of a astable 555 oscillator by using a variable resistance to ground on pin 5. You can vary the length of a pulse of a monostable 555, by using a variable resistance to ground. You can trigger a monostable from a astable oscillator and have a pulse width modulated...
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    kenwood reciever

    Not sure what you have, a short wave receiver that is run on DC? Sometimes the volume potentiometer goes bad and acts like that. You can easily test it with an ohm meter. Just put one lead on the ground or the top and the other on the wiper and turn it and see if the ohms vary smoothly.
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    solar panel voltage regulator

    Thanks, I'll keep that in mind. It's not cheap! I'll wait and let you try it out first and let me know how it works. :)
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    DIY PCB

    I enjoyed your video.Thanks :)
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    solar panel voltage regulator

    Thanks for that info.Yes, they are lead acid. My voltage regulator now is set at 13.8V. Doing that overcharge for 24 hours, would be hard to do since I use the battery power every nite, or on cloudy days.
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    solar panel voltage regulator

    I am building a solar panel voltage regulator to charge 12v batteries, using two 555 ICs. One is just a oscillator and the other is a monostable that I am using to vary the pulse from 0 to 99%. I have already built one that just regulates a steady voltage, but the manufacturers say that a...
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    Multiple Spark CDIS Project

    I see that I'm not the only one that uses a electric fence tester. I would like to build one that would test 30,000 volts, but I don't really understand how they figured the resistors. Here is the value of the resistors if one of you guys wants to build one. They just have a neon lite across...
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    Multiple Spark CDIS Project

    I am still curious to know how you measure the voltage, or is that an estimate?
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    Multiple Spark CDIS Project

    30kV!!!! That should light your fire! And if the first one misses, you have three more chances. How many volts are on the primary? I had 300 on mine and I got at least 9000 volts, maybe more. How do you measure the volts? I used a volt tester for electric fences but maybe you know of a better...
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    Multiple Spark CDIS Project

    So what was the problem and how did you solve it? How many volts does that put out?
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