<div dir="ltr">More answers and insight...<div><br></div><div>I don't want to annoy the forum with too many details, but I'm happy to provide them. This is actually a prototype of a product I'd like to sell on a KickStarter eventually (if it works...)- although my wife still thinks this is a hobby. She's probably right.</div><div><br></div><div>The flashing LED and beeping piezo speaker are pretty easy to do with a 555 timer. I also need around 80Vdc, pulsed about twice per second. The current can be extremely low- just 1 mA or less. The goal is a simple electric field in salt water to annoy fishes, so ripple/noise doesn't matter (no need to rectify it or smooth it with caps). I've seen designs for stun guns that use a 555 timer output into an audio transformer to step up the voltage to 10s of thousands of volts. That would work, but since I only need 80 Vdc, someone else recommended the MAX1771 chip and built a quick prototype using that for me. It also works (and I tested it). Bottom line- it just needs to be cheap and easy.</div><div><br></div><div>Once the design is roughed out, I could still use some help actually building the thing in a PVC pipe. Therefore, if someone would like to pitch in, I'd be happy to buy you coffee/lunch/dinner and talk through the whole thing. If we get this built, I'll present it at a meeting for all of you to chuckle at.</div><div><br></div><div>Meanwhile, my Bitcoin miner arrives tomorrow... so you KNOW I'm crazy...</div><div><br></div><div>db</div><div><br></div><div><br></div><div><br></div><img src="http://t.sidekickopen23.com/e1t/o/5/f18dQhb0S7ks8dDMPbW2n0x6l2B9gXrN7sKj6v4f8fjW1q7dh42BFXSHW5vg7Q82zlZNzW69xng71k1H6H0?si=4964982235594752&pi=fb1b59c7-833f-48a2-c3b9-83810eda23b0" style="display:none!important" height="1" width="1"></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 28, 2015 at 10:42 AM, Brian via TriEmbed <span dir="ltr"><<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Dave,<br>
<br>
Let me echo what others have said, this is a fine forum for your inquiry. So: Where is your high voltage coming from? Are you planning to generate it from the same battery that is powering the rest of the circuit?<br>
<br>
I'm not sure the MAX1771 is going to meet your needs, if you're looking for 80VDC. I'd suggest instead another 555 astable vibrator driving the 8-ohm side of a 8/1000-ohm audio matching transformer. There's some Ohm's Law and transformer math to be done to get just the voltage you want, but the basic idea is the 555 chops your battery voltage (9v?), then the matching transformer steps it up. On the output side, you'd outfit a rectifier and some tank capacitors to smooth it back out to DC.<br>
<br>
Some important considerations:<br>
<br>
How steady do you need your HV to be? Can you tolerate some ripple?<br>
<br>
How important is the actual HV potential? Is 80VDC an important target or could it be higher than that?<br>
<br>
As the HV is switched on/off, can your application handle it ramping rather than switching?<br>
<br>
As an aside, out of a sense of due diligence, does your design include appropriate measures to keep the HV out of reach?<br>
<br>
-B<span class=""><br>
<br>
On 10/27/2015 6:55 PM, Dave Buster via TriEmbed wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
Hi-<br>
I'm a long-time lurker on this email, but I'm not active.<br>
<br>
It's been many, many years since I did Industrial engineering at NC<br>
State, and I've mostly been doing data communications and cyber security<br>
since then. In other words.... I'm no longer hands on. I don't even know<br>
how to solder any more.<br>
<br>
sigh. This is embarrassing..<br>
<br>
Now I have a need to design a build a simple analog circuit for a hobby<br>
of mine, and I'm getting stumped. I'm wondering if someone has some<br>
time to give me a few pointers and/or help me with the design.<br>
<br>
The battery-powered circuit will be very simple. I need to flash an LED<br>
a couple of times per second (I got that working with a 555 timer), then<br>
I need to send beeps to a little piezo speaker (I'm still working on<br>
that), and finally, I need to pulse a high-voltage/low-current DC signal<br>
about twice per second. I'm thinking of using a max1771 DC-DC converter<br>
for that. ...and I'm in over my head.<br>
<br>
I won't be able to make it to the November meeting, but would it be<br>
possible to get someone to spare an hour some other evening to discuss this?<br>
<br>
Anyone want to volunteer to help a life-long learner?<br>
<br>
Here is an email account I don't use very much, but I'll be checking it:<br>
<br>
</span><a href="mailto:dave@tritonsharksignal.com" target="_blank">dave@tritonsharksignal.com</a> <mailto:<a href="mailto:dave@tritonsharksignal.com" target="_blank">dave@tritonsharksignal.com</a>><span class=""><br>
<br>
Also, if this is not appropriate for this email thread, my apologies.<br>
<br>
thanks!<br>
<br>
<br>
<br>
--<br>
Dave Buster<br>
<br>
KK4ELT on 2 meters<br>
Never look at the trombones, it only encourages them.<br></span>
*Ri<br>
<<a href="http://t.sidekickopen23.com/e1t/c/5/f18dQhb0S7lC8dDMPbW2n0x6l2B9nMJW7t5XX45vMtjYVQZgwH64R1y4W8r4TLx56dPn8f5RTxgR02?t=http%3A%2F%2Fwww.brainyquote.com%2Fquotes%2Fauthors%2Fr%2Frichard_wagner.html&si=4964982235594752&pi=6f98b148-9f74-482e-d75c-f87f6847e43c" rel="noreferrer" target="_blank">http://t.sidekickopen23.com/e1t/c/5/f18dQhb0S7lC8dDMPbW2n0x6l2B9nMJW7t5XX45vMtjYVQZgwH64R1y4W8r4TLx56dPn8f5RTxgR02?t=http%3A%2F%2Fwww.brainyquote.com%2Fquotes%2Fauthors%2Fr%2Frichard_wagner.html&si=4964982235594752&pi=6f98b148-9f74-482e-d75c-f87f6847e43c</a>>chard<br>
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</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div><font face="Verdana"><span>Dave Buster</span></font></div><div><font face="Verdana"><span><br></span></font></div><div><font face="Verdana"><span>KK4ELT on 2 meters</span></font></div>
<div><font face="Verdana"><span></span></font> </div>
<div><font face="Verdana"><span>Never look at the trombones, it only encourages them.</span><br><span><b><font color="#0000cc">R<a href="http://t.sidekickopen23.com/e1t/c/5/f18dQhb0S7lC8dDMPbW2n0x6l2B9nMJW7t5XX45vMtjYVQZgwH64R1y4W8r4TLx56dPn8f5RTxgR02?t=http%3A%2F%2Fwww.brainyquote.com%2Fquotes%2Fauthors%2Fr%2Frichard_wagner.html&si=4964982235594752&pi=fb1b59c7-833f-48a2-c3b9-83810eda23b0" target="_blank">i</a>chard Strauss</font></b></span></font><br><br><br></div></div></div>
</div>