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Test Equipment Anonymous (TEA) group therapy thread

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Specmaster:
Yep, they are a good source of cheap drives, especially if you can get them for free or very little.

Edit, stick them in an enclosure and you have cheap backup drive

tautech:

--- Quote from: bd139 on June 11, 2018, 08:58:33 pm ---My TTi supplies have course and fine adjust plus the current pot is a log one. Really the best option IMHO on an analogue supply other than digital setting it via encoder/digital.

--- End quote ---
Nah, course and fine pots are the cheap way out and nothing more.  :P
Never liked that setup at all and refused to stock anything with them.
Right PITA compared to a 10t pot with a good heavy knob that does a few turns when you give it a flick.


--- Quote ---Bloody pot cost more than the rest of the transceiver cost.
--- End quote ---

Sure buying 1x but for manufactures that but them buy 1k, 10k or 100k how much will it really add to the retail cost of a PSU ? Bugger all and provides a nicer cleaner layout.

This is why digital setting has taken off .......cost and better preciseness......but I'm amused you prefer dual pots to 10t or digital but it all depends on how digital is implemented. Encoder only, numeric keypad, up/down buttons or some combination of any/all of them. HW costs of digital has to be cheapest but how it's implemented is the key to usability.

bd139:
People like ‘em.  The newer TTi supplies actually have digital setting and course / fine controls. Literally fastest setting time other than entering the value on a keypad.

Definitely a PITA compared to a 10t with lots of momentum. However if you look at those and I have seen one one some test gear years ago is some chumpty always comes along and ends up killing the end stop in two minutes flat by spinning it to the end.

Decent digital costs serious money. The optical encoder on my Yaesu rig costs £55 a go. If you have to have precise input the “select digit and change” method is just vile. Encoder + keypad are a nice combo.

BUT and this is a big one, how often do you need a really accurate voltage? Within 5% or so is most of electronics. I don’t set my rails to 15.00 and -15.00 volts. Usually one comes up around 14V and the other 15.5. Logic is happy 500mV either way usually. The first receiver I built had 5% components throughout and took a 8-20V supply and was still frequency stable to 20Hz/min drift.

tautech:

--- Quote from: bd139 on June 11, 2018, 10:08:37 pm ---People like ‘em.  The newer TTi supplies actually have digital setting and course / fine controls. Literally fastest setting time other than entering the value on a keypad.

Definitely a PITA compared to a 10t with lots of momentum. However if you look at those and I have seen one one some test gear years ago is some chumpty always comes along and ends up killing the end stop in two minutes flat by spinning it to the end.

Decent digital costs serious money. The optical encoder on my Yaesu rig costs £55 a go. If you have to have precise input the “select digit and change” method is just vile. Encoder + keypad are a nice combo.

BUT and this is a big one, how often do you need a really accurate voltage? Within 5% or so is most of electronics. I don’t set my rails to 15.00 and -15.00 volts. Usually one comes up around 14V and the other 15.5. Logic is happy 500mV either way usually. The first receiver I built had 5% components throughout and took a 8-20V supply and was still frequency stable to 20Hz/min drift.

--- End quote ---
Yep, rarely and just the point I made a few posts back WRT 5t pots.

However modern digital PSU's have some decent acceleration logarithms acting on the encoder so are pretty decent to use compared to step by step increments. Others have memory that you set for your commonly used values and jump to them with a couple of key presses.

tggzzz:

--- Quote from: bd139 on June 11, 2018, 10:08:37 pm ---BUT and this is a big one, how often do you need a really accurate voltage?

--- End quote ---

If you are doing linearity testing, it can be convenient to step in accurate increments. Ditto sensisitity testing.

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