Multiturn potentiometer ~500k >=2W

ErikdeBest · 7th May 2010, 10:28 AM

I am going to build some HV power bench supplies based on the LR8N3 IC and a big HV mosfet as pass element. I already have some single-turn 400k/2W potentiometers, but have been looking into multiturn potentiometers to allow for finer adjustment of the output voltage. The value should be around 500k, with a wattage rating of 2W or more. I found some on mouser: Bourns unit for 160 euro, Bitechnologies is cheaper at 44 euro, and then there is also Vsensor for which I could not find a price... but, maybe some member can sell me some for a nicer price?

theAnonymous1 · 7th May 2010, 04:45 PM

There are some 4W Mallory on e*ay, but the shipping is a little much for a pot and they don't mention overseas shipping.

Mallory Model: M500PK Potentiometer. 500K OHM, 4 Watts< - eBay (item 270386595328 end time May-31-10 16:47:14 PDT)

ErikdeBest · 10th May 2010, 03:10 PM

hi!

Many thanks for the reply. I am looking for multiturn pots, however, as I already have some single-turns that work fine for me (but do not allow for finer adjustment).

Many thanks! Erik

kavermei · 11th May 2010, 02:38 PM

Looks like a tall order. How about using a switch for coarse adjustment and a pot for fine adjustment (like on some scopes)?

Kenneth

ErikdeBest · 11th May 2010, 02:45 PM

Hi Kenneth

I think you are right, it is going to be hard to find these WW units for an 'affordable' price. My alternative is to connect two pots (400k and ~40k) in series to allow for coarse and fine adjustments, but I will look into the switch option as well. Do you have any suggestions for a nice switch? I would like to switch it 'live', so it should be able to handle DC switching of relatively high voltages.

Erik

kavermei · 11th May 2010, 03:09 PM

Erik,

the old russian stuff would be ideal, check for example eBay Winkel - KW TUBES: Wij verkopen Capacitors, Tubes, Crystals. Kopen en verkopen op eBay.be and click on "Switches" in the menu at the left.

I have some of the ceramic types at home, they sure look like they can take some voltage. Contact are silver plated and must be cleaned after all those years of storage. Not sure about the brown types.

Very cheap, too!

Kenneth

7th May 2010, 10:28 AM	#1
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Multiturn potentiometer ~500k >=2W I am going to build some HV power bench supplies based on the LR8N3 IC and a big HV mosfet as pass element. I already have some single-turn 400k/2W potentiometers, but have been looking into multiturn potentiometers to allow for finer adjustment of the output voltage. The value should be around 500k, with a wattage rating of 2W or more. I found some on mouser: Bourns unit for 160 euro, Bitechnologies is cheaper at 44 euro, and then there is also Vsensor for which I could not find a price... but, maybe some member can sell me some for a nicer price? __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

7th May 2010, 04:45 PM	#2
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	There are some 4W Mallory on e*ay, but the shipping is a little much for a pot and they don't mention overseas shipping. Mallory Model: M500PK Potentiometer. 500K OHM, 4 Watts< - eBay (item 270386595328 end time May-31-10 16:47:14 PDT) __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

10th May 2010, 03:10 PM	#3
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	hi! Many thanks for the reply. I am looking for multiturn pots, however, as I already have some single-turns that work fine for me (but do not allow for finer adjustment). Many thanks! Erik __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!

11th May 2010, 02:38 PM	#4
kavermei diyAudio Member Join Date: Jan 2005 Location: Lokeren, Belgium	Looks like a tall order. How about using a switch for coarse adjustment and a pot for fine adjustment (like on some scopes)? Kenneth __________________ Never send a human to do a machine's job. --Agent Smith

11th May 2010, 02:45 PM	#5
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Hi Kenneth I think you are right, it is going to be hard to find these WW units for an 'affordable' price. My alternative is to connect two pots (400k and ~40k) in series to allow for coarse and fine adjustments, but I will look into the switch option as well. Do you have any suggestions for a nice switch? I would like to switch it 'live', so it should be able to handle DC switching of relatively high voltages. Erik __________________ my surname is indeed 'de Best': neither misspelling nor snobbism! Ask SY!


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11th May 2010, 03:09 PM	#6
kavermei diyAudio Member Join Date: Jan 2005 Location: Lokeren, Belgium	Erik, the old russian stuff would be ideal, check for example eBay Winkel - KW TUBES: Wij verkopen Capacitors, Tubes, Crystals. Kopen en verkopen op eBay.be and click on "Switches" in the menu at the left. I have some of the ceramic types at home, they sure look like they can take some voltage. Contact are silver plated and must be cleaned after all those years of storage. Not sure about the brown types. Very cheap, too! Kenneth __________________ Never send a human to do a machine's job. --Agent Smith

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