In Europe the Vat =18-21 %.
PS: @Dave: After reading a PDF on the web... What is the burden voltage of your Fluke 87? No looking it up!
PS: @Dave: After reading a PDF on the web... What is the burden voltage of your Fluke 87? No looking it up!
Considering that would be likely written by me :->, I should be able to get this right from memory - 1.8mV/mA?
Dave.
My design will be using an LM317 instead of the LT3080 because no one seems to sell them in the UK. I've also kept the current limiting opamp instead of the custom current IC.
My design will be using an LM317 instead of the LT3080 because no one seems to sell them in the UK. I've also kept the current limiting opamp instead of the custom current IC.
Ebay has them
My design will be using an LM317 instead of the LT3080 because no one seems to sell them in the UK.
My design will be using an LM317 instead of the LT3080 because no one seems to sell them in the UK.
Farnell appears to have them in the TO-220-5 package at £4.17 each. Is there a hidden catch I am missing?
"US Stock items that have a service charge indicated are coming from our Newark warehouse. The service charge will be £15.95 per order, in lieu of a freight charge for Newark items."
So this is why I would suggest a group buy. Order we could put pressure to Farnell to stock them locally in the UK.
"US Stock items that have a service charge indicated are coming from our Newark warehouse. The service charge will be £15.95 per order, in lieu of a freight charge for Newark items."
So this is why I would suggest a group buy. Order we could put pressure to Farnell to stock them locally in the UK.
Ah, that's a bit of a gotcha. But it looks like the SOT-223 package is in stock locally and it's cheaper too. Wouldn't that be an acceptable substitution?
Such a small package would very hard, if not impossible to keep cool. See the datasheet for an example.
Such a small package would very hard, if not impossible to keep cool. See the datasheet for an example.
Hmm. The datasheet gives a thermal resistance of 3 K/W between junction and case for the TO-220 package, but it does not give an equivalent number between junction and tab for the SOT-223 package. That makes like-for-like comparisons rather difficult. I had thought perhaps to solder the SOT-223 package to a copper heat sink by its tab and use flying leads to the pins. In other words to to turn the SMT part into a make-shift through hole part. For home build construction you don't always have to mount devices in the manner intended for automated production. Would be hard of course with aluminium heat sinks.
I'm not sure how feasible it might be...
The datasheet has all the thermal specs for the different packages on the second page of the data sheet. The SOT package is 15 DegC/W. The two surface mount packages with 3 DegC/W are the 8 lead plastic DFN package and the 5 lead DD-PAK package. I would think the DD-PAK has the bigger heatsink tab area, so it will probably make the best thermal connection to the heatsink.
I think as a first power supply something in the generic 0-30v 0-5A range would be better suited.
I think as a first power supply something in the generic 0-30v 0-5A range would be better suited.
But why? What is the basic electronics experimenter going to do with such a beast?
For every electronics need I have encountered, 0-12 V and 0-1 A has been more than sufficient.
If I have needed more power than that it has been for non-electronics applications like driving lamps or motors. And for that a linear supply is scarcely necessary. A cheaper switch mode supply does just fine.
A typical beginner isn't going to want to have to get two power supplies, so it really seems like a valid goal to try to make the first one as versatile as is reasonably possible.
I think as a first power supply something in the generic 0-30v 0-5A range would be better suited.
But why? What is the basic electronics experimenter going to do with such a beast?
For every electronics need I have encountered, 0-12 V and 0-1 A has been more than sufficient.
If I have needed more power than that it has been for non-electronics applications like driving lamps or motors. And for that a linear supply is scarcely necessary. A cheaper switch mode supply does just fine.
A typical beginner isn't going to want to have to get two power supplies, so it really seems like a valid goal to try to make the first one as versatile as is reasonably possible.It's quite common to need multiple power supplies, so I'm not sure if I agree with your assertion. You may need multiple power supply to provide 12/24V for motors and 5V for logic for example, or 5V and 3.3V logic, or to provide symmetrical power supplies for op-amps. Might as well get two and put them in series/parallel for higher voltage/current.
Obviously different people will have different needs but i wouldn't recommend a supply with less than 12V for a first supply which is what Daves will be