Carl, I think we can all agree that ideally, we should always have an "adequate" power supply. However, sadly, I didn't get one for christmas. [noparse]:([/noparse]
Since it sounds like he doesn't have an adequate power supply, the diodes seem to be needed. You can always get schottky diodes. I've got some with a 0.33V drop. You can get some even lower... $0.05 in diodes is well worth it compared to a beefier power supply, but that's just my opinion...
kwinn said...
3000F at 1000V would be more like a rail cannon or possibly orbital launcher. Charging them might even cause a blackout
Wow, 1500 megajoules.· That's 'prox 417 KWH of energy, about 50-75 bucks on your light bill.· It'd take a while to charge it fully, and it would pack a terrific punch.· Lessee -- you could use it to tase woolly mammoths, Kzinti, or Bandersnatchi.
Back to my original problem. I seperated the servos to battery power with common ground. No flicker and the voltage regulators stay cool. Any other ideas??
Thanks.
Everybody is worrying about the positive side of the power supplies. I was pondering on the negative sideas well, are all the "earths and supplies" fed dirrectly from the source, in a star?
I have found the reset cct of the prop (demo board ) a bit trigger happy. My 'scope being swithed off resets it even when not connected apart from the mains (via 9V SMPSU, 5V reg then 3.3V reg )
Attached are 3 schematics I use as a starting point for any power supply I build. I put a 3 pin terminal strip between the bridge rectifier/transformer center tap and the regulator board, and connect any motor/drive circuit directly to the terminal strip. I make sure one of the connections on the terminal strip is used as the common/ground point for all the circuitry to avoid problems with ground loops and noise pickup.
This layout works very well and the only time I have had problems with the microcontroller/logic resetting is when the motor draws more current than the transformer can supply for more than a couple of cycles of the AC line. If that happens you need a heftier transformer and bridge rectifier. It also works very well if the transformer/rectifier is replaced with a battery.
I just went back to your original post question. You said that you purchased a 7.5V @ 1A PSU "for" parallax, did you mean from Parallax or some other some other place to be used for the Prop.
I only ask because there are all sorts of Smile PSUs out there which may give the stated volts at that stated current, when open cct they give out more than double that with enough lump, bumps and spikes to rival the tail end of a hedgehog. Your phone charger will almost certainly be a switch mode and so properly regulated.
I am sure that is a joke but it got lost some where. never herd of a breakfast cap
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Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
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Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
Comments
Since it sounds like he doesn't have an adequate power supply, the diodes seem to be needed. You can always get schottky diodes. I've got some with a 0.33V drop. You can get some even lower... $0.05 in diodes is well worth it compared to a beefier power supply, but that's just my opinion...
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· -- Carl, nn5i@arrl.net
I'm salivating at the thought of a 1.5GJ bank.
Now that's what I call EE porn.
Thanks.
I have found the reset cct of the prop (demo board ) a bit trigger happy. My 'scope being swithed off resets it even when not connected apart from the mains (via 9V SMPSU, 5V reg then 3.3V reg )
This layout works very well and the only time I have had problems with the microcontroller/logic resetting is when the motor draws more current than the transformer can supply for more than a couple of cycles of the AC line. If that happens you need a heftier transformer and bridge rectifier. It also works very well if the transformer/rectifier is replaced with a battery.
I scavanted a motorola cell phone v 500 ma supply and found it successful in eliminating the problem.
Thanks for all the suggestions.
I only ask because there are all sorts of Smile PSUs out there which may give the stated volts at that stated current, when open cct they give out more than double that with enough lump, bumps and spikes to rival the tail end of a hedgehog. Your phone charger will almost certainly be a switch mode and so properly regulated.
Thanks for all the help.
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· -- Carl, nn5i@arrl.net
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.