Whites Surf PI schematic

[Andi68]

But the Baracuda also draws much more power than the surf, I measured 120mA, and I think that kills the 7660 even more

[Qiaozhi]

I think you get me wrong.I have no doubt about the parameters. Just need confirmation that 10volt 7660 will work in 12v powered surf PI. For Bara it is clear one need 12v 7660S or 7660A. Thanks.

For the Baracuda even the 12V versions of the 7660 are not sufficient, as 12V is the nominal voltage, and the maximum voltage can be as high as 13.2V. Eventually the 7660 will let out the magic smoke.

[nonkapo]

I think you get me wrong.I have no doubt about the parameters. Just need confirmation that 10volt 7660 will work in 12v powered surf PI. For Bara it is clear one need 12v 7660S or 7660A. Thanks.

[dbanner]

I can't say, try looking to DATASHEET of various devices to compare operating parameters.

[nonkapo]

Sorry for the diletants question, but comparing the schematics of Baracuda and Surf PI which i'm working on together i've just notice something. The power in the surf PI is going to 7660 only after regulated to 5V by 7805, so i hope that mean any version of 7660 will work in difference to Baracuda, where the power go directly to 7660 and you need to use 7660S or LT1050 tolerating respectively 12 and 15 volts? So as conclusion 7660 or7660A will not make any difference to using 7660S or LT1050? Also if Is it possible to directly fit LT1050 on the place of 7660 without modifications(despite i do not see advantage here unlike in the Bara)?
Thanks

[dbanner]

I just realized that I used biggish wire wound pot, maybe this is good for setting, but not good for permanent, as the pot itself is susceptible.

[dbanner]

Inductance doesn't change with temperature, but resistances do, so the q of coil . might change.(the parasitics)
My coil isn't potted in anything and she is not shielded, so maybe that's why she is like grasshopper
Maybe also EMI, she is not happy

[dbanner]

You can maybe put switch, but added capacitance is bad. The less you have between coil and her MOSFET, she is happy.

[dbanner]

I am not sure if ambient temperature is the issue here. I don't have any scientific testing like the pros in science lab. All I can say is my experience. There is phenomenon known as"ringing", which is why coil must be with damping resistor. Once she is set, it should remain, but I noticed on my self made, she is sometimes slightly off to give best sensitivity, so I tweak with pot with gold ring for best results at beach, no scope, primitive method. I am interested in finding stuff, not staring at oscilloscope the entire day. Besides I made several coils which I can adjust damping resistor easy by tweaking the pot while swinging ring for best sensitivity. Can't put scope at beach

[localbug]

If damping resistor gets warmer, I think higher power rating resistor should be used. Most of the electronics components are temperature sensitive, using high quality components will make your detector performance at maximum. Adding a cooler can be an alternative.

[nonkapo]

Were there variations in temperature?

Some components react to it

Yes, he mention some 12 degrees. Poor me, i dont know what to expect with my nearly 25 to 30 degrees difference in the summer months.... So in my case must be compulsory to set up such pot.
Y

[Andi68]

Were there variations in temperature?

Some components react to it

[dbanner]

My coil isn't potted in anything. It is a flat coil wound with copper wire onto ply wood and painted with kind of water seal.

[dbanner]

Yes, I know. There is a sweet spot in damping where my self made surf detects at maximum distance. But I noticed it varies ever so slightly on different days. I set it up today, and maybe tomorrow is good or not so good. So I got fed up having to go inside the box and just made it on back panel of box. Those 2 extra inches are important. The other reason is that when I use headphones, I have to readjust damping compared to using the speaker that I have mounted in the box. I use small Audio transformer to drive the speaker output.

[6666]

The difference can be as much as a few inches.

I am frustrated and perplexed by this result, surely there must be something else going on here other than temperature ?