No More TO-3 Voltage Regulators?...

[Computer Nerd Kev]

Looking for a replacement LM340K-24 fixed 24V 1A linear regulator
for my bench power supply I\'ve dicovered that TO-3 voltage regulators
seem to be in the last stages of disappearing entirely.

Looking at all the whole category of TO-3 voltage regulators:

RS only have 4 models, and want around $100 to buy them individually:
https://au.rs-online.com/web/c/semiconductors/power-management-ics/linear-voltage-regulators/?applied-dimensions=4294575049

Element 14 have 6 models and mostly similar pricing:
https://au.element14.com/w/c/semiconductors-ics/power-management-ics-pmic/voltage-regulators/linear-voltage-regulators?linear-regulator-case-style=to-3

None are fixed 24v regulators. (Rockby do have some TO-3 regs cheap,
but no +24V ones there either).

TI don\'t list any TO-3 package LM340s being made:
https://www.ti.com/product/LM340

It looks like the only option might be NOS sellers on Ebay, and there
aren\'t even any of those in Australia...

I guess everyone\'s using switch-mode regulators for higher power
applications now, though I\'m still surprised that such a previously
common package for a range of still-common components has gone out
of production.

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#_ < |\\| |< _#

 

[Phil Allison]

Computer Nerd Kev wrote:

========================

Looking for a replacement LM340K-24 fixed 24V 1A linear regulator
for my bench power supply I\'ve dicovered that TO-3 voltage regulators
seem to be in the last stages of disappearing entirely.

It looks like the only option might be NOS sellers on Ebay, and there
aren\'t even any of those in Australia...

** Nonsense:

WES Components have the LM338K, 5A, 1.2V to 40V reg for $7 or $8+

Best TO3 reg ever made, phenomenal specs.

They also have the L7812CT 1.5A, 12V for about $3 in TO3

Use a 12V zener on the ground pin to get 24V.

Maybe snap a few up.


...... Phil

 

[Computer Nerd Kev]

Phil Allison <pallison49@gmail.com> wrote:

Computer Nerd Kev wrote:

========================

Looking for a replacement LM340K-24 fixed 24V 1A linear regulator
for my bench power supply I\'ve dicovered that TO-3 voltage regulators
seem to be in the last stages of disappearing entirely.

It looks like the only option might be NOS sellers on Ebay, and there
aren\'t even any of those in Australia...


** Nonsense:

WES Components have the LM338K, 5A, 1.2V to 40V reg for $7 or $8+

Best TO3 reg ever made, phenomenal specs.

They also have the L7812CT 1.5A, 12V for about $3 in TO3

Use a 12V zener on the ground pin to get 24V.

Hmm, yeah silly me, I forgot about that option. I\'ve got three 7812s
in TO-3 package already.

--
__ __
#_ < |\\| |< _#

 

[Phil Allison]

Computer Nerd Kev wrote:

===========================

Looking for a replacement LM340K-24 fixed 24V 1A linear regulator
for my bench power supply I\'ve dicovered that TO-3 voltage regulators
seem to be in the last stages of disappearing entirely.

It looks like the only option might be NOS sellers on Ebay, and there
aren\'t even any of those in Australia...


** Nonsense:

WES Components have the LM338K, 5A, 1.2V to 40V reg for $7 or $8+

Best TO3 reg ever made, phenomenal specs.

They also have the L7812CT 1.5A, 12V for about $3 in TO3

Use a 12V zener on the ground pin to get 24V.

Hmm, yeah silly me, I forgot about that option. I\'ve got three 7812s
in TO-3 package already.

** Good, I like TO3 stuff too but in reality TO220 versions do the same job if dissipation is under 20W or up to 45W for the LM338.

Use thin mica, white grease and clamp the things rather that use the bolt hole for best results.

Just looked at my parts bin and found a variety of TO3 regs :

2 x LM338K
2 x LM317K
1 x LM337K
1 x L7805CT
2 x LT1033


...... Phil