Hey Ron,<br><br>><font><font color="#000000" face="Arial" size="2"> I guess my tiny13 won't be driving the beasties.</font></font><br>><font><font color="#000000" face="Arial" size="2"> I really like the idea of not having to involve an h-bridge or driver
transistors/fets -- too much complexity.<br><br>Oh, transistors are our friends! And they work with no nasty opcodes to remember.<br></font></font><br>Here's a new (to me) transistor that might do the trick. 3V looks marginal, though. Using a 5V supply, these will work great. (~300mA with a Vgs of 4V)
<br> <br>It's a 2N7002, an N-channel FET made for low-voltage power switching. <br><br><a href="http://www.fairchildsemi.com/ds/2N/2N7002.pdf">http://www.fairchildsemi.com/ds/2N/2N7002.pdf</a><br><br>I'll buy some of the thru-hole parts with my next Digi-Key order, and let everyone know how they work.
<br><br>-Jeff<br><br><br><br><div class="gmail_quote">On Jan 1, 2008 7:23 PM, <<a href="mailto:DeltaGraph@aol.com">DeltaGraph@aol.com</a>> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div style="font-size: 10pt; color: rgb(0, 0, 0); font-family: Arial;"><font color="#000000" face="Arial" size="2">
<div>Hey Jeff, Thanks</div>
<div> </div>
<div>Thinking on PWMing motors</div>
<div> </div>
<div>I guess my tiny13 won't be driving the beasties.</div>
<div>Maybe Tiny26 -- Dale mentioned that part drives 40 mA per pin - so I looked
it up</div>
<div>200 mA for total part -- so reasonable. So I assume could tie 3
pins and pretty much drive motor.</div>
<div> </div>
<div>Of course would lose out on direct PWM output, but PWM gen can generate
soft interrupts which could </div>
<div>be used to twiddle bits on multiple pins.</div>
<div> </div>
<div>Tiny26 will run at 3 volts -- could always current limit motors just a tad
with series resistance.</div>
<div>I assume motors would not kill Tiny's pins with flyback spikes. Oh well, $2
down the drain if they do.</div>
<div> </div>
<div>I really like the idea of not having to involve an h-bridge or driver
transistors/fets -- too much complexity</div>
<div> </div>
<div>I know connecting 24 volts to an AVR pin will blow it.</div>
<div>Did get away with driving one on a Mega128 to almost dead short (8 ohm
speaker) for some time and it survived. The chip was running real hot -- then I
discovered a series resistor was shorted.</div>
<div> </div>
<div> </div>
<div>Ron</div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div> </div></font><div class="Ih2E3d"><br><br><br><div><font style="color: black; font-family: ARIAL,SAN-SERIF; font-style: normal; font-variant: normal; font-weight: normal; font-size: 10pt; line-height: normal; font-size-adjust: none; font-stretch: normal;">
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</font></div></div></div>
</blockquote></div><br>