> Can anyone suggest anything ? A 1 amp device with I adj. from 100mA up ...
> Does it exist ?
Linear, no.
I'd look at some of the USB power switches with adjustable current limits, i.e. <http://www.micrel.com/_PDF/mic2544.pdf>. You'd need a linear regulator in front of it though, since the input is limited to 7V.
ILIM sets the output current limit without requiring a 2W
potentiometer.
Design of ILIM is left as an exercise for the student :-) Caution, a
negative auxiliary supply of at least -1.25V will be required to pull
output all the way to zero volts.
A similar approach should work with the two-LM317-in-series
presentation
...Jim Thompson
-- | James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
>ILIM sets the output current limit without requiring a 2W
>potentiometer.
>Design of ILIM is left as an exercise for the student :-) Caution, a
>negative auxiliary supply of at least -1.25V will be required to pull
>output all the way to zero volts.
Or add some diodes to drop the output, then the TL431 loop.
>A similar approach should work with the two-LM317-in-series
>presentation
> ...Jim Thompson
...Jim Thompson
-- | James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
>>>> LM78x05, LM317 are good for the forseeable future.
>>> But no adjustable current limit which is what the OP wants. If I needed
>>> fairly precise current limit and it was all on a tight budget I'd try
>>> to
>>> use a TL494 as a linear regulator. That thing will likely be around
>>> until you and I can't hold a soldering iron no more.
>> Thanks for all the replies.... I didn't quite express myself
>> correctly.... I
>> should have said 'selectable' as opposed to 'adjustable'.
>> The adjustable solutions require too much effort ( for these simple
>> test box
>> setups).
>> The optimum was mentioned by a few and thanks- I'll go with the 317
>> (actually 1117DT) and current limit resistor with adequate wattage for
>> each
>> solution. The pot idea was good but would need a 2W+ pot lol.
>> My favourite 5V reg is the LM2940..
>> The reason for current limiting is to prevent 'smokers' if there is a
>> short
>> on the UUT.... due to piss poor inspection :)
> Polyfuses are good for fire prevention. The radial leaded ones work
> well; the surface-mount ones less well.
> I like to use a polyfuse and a transzorb on DC voltage inputs to my
> boxes, for overvoltage/transient/reverse polarity protection.
> I also have used an LM317L TO92 as a current limiter, with the adj pin
> floating. It works great, but loses about 1.5 volts. I wish there was
> an equivalent lower dropout on-purpose current limiter.
On Sun, 01 Apr 2012 11:35:44 -0700, John Larkin wrote:
> On Sun, 1 Apr 2012 09:56:29 +0100, "TTman" <pcw1....@ntlworld.com>
> wrote:
>>>> LM78x05, LM317 are good for the forseeable future.
>>> But no adjustable current limit which is what the OP wants. If I
>>> needed fairly precise current limit and it was all on a tight budget
>>> I'd try to use a TL494 as a linear regulator. That thing will likely
>>> be around until you and I can't hold a soldering iron no more.
>>Thanks for all the replies.... I didn't quite express myself
>>correctly.... I should have said 'selectable' as opposed to
>>'adjustable'.
>>The adjustable solutions require too much effort ( for these simple test
>>box setups).
>>The optimum was mentioned by a few and thanks- I'll go with the 317
>>(actually 1117DT) and current limit resistor with adequate wattage for
>>each solution. The pot idea was good but would need a 2W+ pot lol.
>>My favourite 5V reg is the LM2940..
>>The reason for current limiting is to prevent 'smokers' if there is a
>>short on the UUT.... due to piss poor inspection :)
> Polyfuses are good for fire prevention. The radial leaded ones work
> well; the surface-mount ones less well.
> I like to use a polyfuse and a transzorb on DC voltage inputs to my
> boxes, for overvoltage/transient/reverse polarity protection.
> I also have used an LM317L TO92 as a current limiter, with the adj pin
> floating. It works great, but loses about 1.5 volts. I wish there was an
> equivalent lower dropout on-purpose current limiter.
Please refer to the figure in the datasheet labelled "Current Source".
Important: it only gives low dropout if you have an independent bias supply.
Dropout is about 350mV from the main input and about 1.35V from the bias input.
See also LT3082, '3083, '3085.
Disclaimer: I haven't used these particular parts in any design.
On a sunny day (Sun, 01 Apr 2012 15:10:58 -0700) it happened Jim Thompson
<To-Email-Use-The-Envelope-I...@On-My-Web-Site.com> wrote in
<h7khn75mgcqjrba2fi4t23lv4l2autv...@4ax.com>:
>ILIM sets the output current limit without requiring a 2W
>potentiometer.
>Design of ILIM is left as an exercise for the student :-) Caution, a
>negative auxiliary supply of at least -1.25V will be required to pull
>output all the way to zero volts.
>A similar approach should work with the two-LM317-in-series
>presentation
> ...Jim Thompson
What I do not understand is why not just put a PNP in front of a LM117,
and use the beta:
PNP <1A in out
+12 ------ e c ----------------- LM317 -------------> out
b | | | |
| === 150 [ ] | ===
470 [ ] <10mA | |--- |
| /// | ///
4k7 [ ]<-- [ ]<---
| | Imax | | Uout
/// /// /// ///
Find one with a beta > 100, normally it will be on and drop less than 300 mV,
should be on heatsink too as it will get hot if it limits.
Beta does not really change THAT much.
I have used this sort of limiter, and it works great.
> Michael, On paper, it works. However, how that LM317 "floats" is
> indeterminate. Possibly it just saturates up against the positive
> rail until current limit is reached.
I'm mistreating the pot. probably enough to destroy it, it probably
needs a 12W part instead of the 1W shown.
if your prepared to program the current limit in binary it's possibly
even cheaper, eg: some number of 12R in parallel, each is good for 100mA of headroom.
-- ⚂⚃ 100% natural
--- Posted via news://freenews.netfront.net/ - Complaints to n...@netfront.net ---
>> > Does that mess come with a fire extinguisher?
> I know that it works on paper, but to need high wattage resistors is
> just poor design. That one watt pot would likely be wirewound, and very
> noisy when it's adjusted.
the brief (as I understood it) was a linear regulator with a 12V supply
every watt that's burned in a resistor isn't being used to warm the
heatsink,
use 1 to 10 12 ohm 1/4W resistors in parallel for the current selection.
-- ⚂⚃ 100% natural
--- Posted via news://freenews.netfront.net/ - Complaints to n...@netfront.net ---
On Sunday, April 1, 2012 11:04:48 PM UTC-4, Allan Herriman wrote:
> On Sun, 01 Apr 2012 11:35:44 -0700, John Larkin wrote:
> > On Sun, 1 Apr 2012 09:56:29 +0100, "TTman"
> > wrote:
> >>>> LM78x05, LM317 are good for the forseeable future.
> >>> But no adjustable current limit which is what the OP wants. If I
> >>> needed fairly precise current limit and it was all on a tight budget
> >>> I'd try to use a TL494 as a linear regulator. That thing will likely
> >>> be around until you and I can't hold a soldering iron no more.
> >>Thanks for all the replies.... I didn't quite express myself
> >>correctly.... I should have said 'selectable' as opposed to
> >>'adjustable'.
> >>The adjustable solutions require too much effort ( for these simple test
> >>box setups).
> >>The optimum was mentioned by a few and thanks- I'll go with the 317
> >>(actually 1117DT) and current limit resistor with adequate wattage for
> >>each solution. The pot idea was good but would need a 2W+ pot lol.
> >>My favourite 5V reg is the LM2940..
> >>The reason for current limiting is to prevent 'smokers' if there is a
> >>short on the UUT.... due to piss poor inspection :)
> > Polyfuses are good for fire prevention. The radial leaded ones work
> > well; the surface-mount ones less well.
> > I like to use a polyfuse and a transzorb on DC voltage inputs to my
> > boxes, for overvoltage/transient/reverse polarity protection.
> > I also have used an LM317L TO92 as a current limiter, with the adj pin
> > floating. It works great, but loses about 1.5 volts. I wish there was an
> > equivalent lower dropout on-purpose current limiter.
> Please refer to the figure in the datasheet labelled "Current Source".
> Important: it only gives low dropout if you have an independent bias > supply.
> Dropout is about 350mV from the main input and about 1.35V from the bias > input.
> See also LT3082, '3083, '3085.
> Disclaimer: I haven't used these particular parts in any design.
In article <jl6ej5$58...@dont-email.me>, TTman <pcw1....@ntlworld.com> wrote:
>Can anyone suggest anything ? A 1 amp device with I adj. from 100mA up ...
>Does it exist ?
The L200 used to exist. A 5 pin TO-220. Like a 317 with a adjustable current limit set by external components. SGS-ATES, maybe ST now.
Rather low power dissipation, so putting too many volts in was problematic. With a higher (than a LM317) dropout voltage, too.
Mark Zenier mzen...@eskimo.com
Googleproofaddress(account:mzenier provider:eskimo domain:com)
bloggs.fredbloggs.f...@gmail.com wrote:
> On Sunday, April 1, 2012 11:04:48 PM UTC-4, Allan Herriman wrote:
>> On Sun, 01 Apr 2012 11:35:44 -0700, John Larkin wrote:
>>>>>> LM78x05, LM317 are good for the forseeable future.
>>>>> But no adjustable current limit which is what the OP wants. If I
>>>>> needed fairly precise current limit and it was all on a tight budget
>>>>> I'd try to use a TL494 as a linear regulator. That thing will likely
>>>>> be around until you and I can't hold a soldering iron no more.
>>>>> --
>>>>> Regards, Joerg
>>>>> http://www.analogconsultants.com/ >>>> Thanks for all the replies.... I didn't quite express myself
>>>> correctly.... I should have said 'selectable' as opposed to
>>>> 'adjustable'.
>>>> The adjustable solutions require too much effort ( for these simple test
>>>> box setups).
>>>> The optimum was mentioned by a few and thanks- I'll go with the 317
>>>> (actually 1117DT) and current limit resistor with adequate wattage for
>>>> each solution. The pot idea was good but would need a 2W+ pot lol.
>>>> My favourite 5V reg is the LM2940..
>>>> The reason for current limiting is to prevent 'smokers' if there is a
>>>> short on the UUT.... due to piss poor inspection :)
>>> Polyfuses are good for fire prevention. The radial leaded ones work
>>> well; the surface-mount ones less well.
>>> I like to use a polyfuse and a transzorb on DC voltage inputs to my
>>> boxes, for overvoltage/transient/reverse polarity protection.
>>> I also have used an LM317L TO92 as a current limiter, with the adj pin
>>> floating. It works great, but loses about 1.5 volts. I wish there was an
>>> equivalent lower dropout on-purpose current limiter.
>> Please refer to the figure in the datasheet labelled "Current Source".
>> Important: it only gives low dropout if you have an independent bias >> supply.
>> Dropout is about 350mV from the main input and about 1.35V from the bias >> input.
>> See also LT3082, '3083, '3085.
>> Disclaimer: I haven't used these particular parts in any design.
>> Regards,
>> Allan
> That's a $4 part...
Ever heard pilots talking about their $100 hamburgers? :-)
> >>>>>> LM78x05, LM317 are good for the forseeable future.
> >>>>> But no adjustable current limit which is what the OP wants. If I
> >>>>> needed fairly precise current limit and it was all on a tight budget
> >>>>> I'd try to use a TL494 as a linear regulator. That thing will likely
> >>>>> be around until you and I can't hold a soldering iron no more.
> >>>>> --
> >>>>> Regards, Joerg
> >>>>> http://www.analogconsultants.com/ > >>>> Thanks for all the replies.... I didn't quite express myself
> >>>> correctly.... I should have said 'selectable' as opposed to
> >>>> 'adjustable'.
> >>>> The adjustable solutions require too much effort ( for these simple test
> >>>> box setups).
> >>>> The optimum was mentioned by a few and thanks- I'll go with the 317
> >>>> (actually 1117DT) and current limit resistor with adequate wattage for
> >>>> each solution. The pot idea was good but would need a 2W+ pot lol.
> >>>> My favourite 5V reg is the LM2940..
> >>>> The reason for current limiting is to prevent 'smokers' if there is a
> >>>> short on the UUT.... due to piss poor inspection :)
> >>> Polyfuses are good for fire prevention. The radial leaded ones work
> >>> well; the surface-mount ones less well.
> >>> I like to use a polyfuse and a transzorb on DC voltage inputs to my
> >>> boxes, for overvoltage/transient/reverse polarity protection.
> >>> I also have used an LM317L TO92 as a current limiter, with the adj pin
> >>> floating. It works great, but loses about 1.5 volts. I wish there was an
> >>> equivalent lower dropout on-purpose current limiter.
> >> Please refer to the figure in the datasheet labelled "Current Source".
> >> Important: it only gives low dropout if you have an independent bias > >> supply.
> >> Dropout is about 350mV from the main input and about 1.35V from the bias > >> input.
> >> See also LT3082, '3083, '3085.
> >> Disclaimer: I haven't used these particular parts in any design.
> >> Regards,
> >> Allan
> > That's a $4 part...
> Ever heard pilots talking about their $100 hamburgers? :-)
On Saturday, March 31, 2012 5:50:32 AM UTC-4, TTman wrote:
> "John Fields" <jfie...@austininstruments.com> wrote in message > news:gnkdn7lcl62q5qmk80at51tbaogghq1bns@4ax.com...
> > On Sat, 31 Mar 2012 09:17:33 +0100, "TTman"
> > wrote:
> >>Can anyone suggest anything ? A 1 amp device with I adj. from 100mA up ...
> >>Does it exist ?
> > ---
> > Input voltage range?
> > -- > > JF
> Oooops 12V fixed.
With those kind of voltages, you could do something like this with junkbox parts. It's a simple highside current monitor driving a low RDS,ON MOSFET in foldback mode. Any 5V regulator will work. If you don't like the rheostat then replace it with a DPST to select a 10R for 100mA or a 100R for 1A trip. Please view in a fixed-width font such as Courier.
bloggs.fredbloggs.f...@gmail.com wrote:
>On Saturday, March 31, 2012 5:50:32 AM UTC-4, TTman wrote:
>> "John Fields" <jfie...@austininstruments.com> wrote in message >> news:gnkdn7lcl62q5qmk80at51tbaogghq1bns@4ax.com...
>> > On Sat, 31 Mar 2012 09:17:33 +0100, "TTman"
>> > wrote:
>> >>Can anyone suggest anything ? A 1 amp device with I adj. from 100mA up ...
>> >>Does it exist ?
>> > ---
>> > Input voltage range?
>> > -- >> > JF
>> Oooops 12V fixed.
>With those kind of voltages, you could do something like this with junkbox parts. It's a simple highside current monitor driving a low RDS,ON MOSFET in foldback mode. Any 5V regulator will work. If you don't like the rheostat then replace it with a DPST to select a 10R for 100mA or a 100R for 1A trip. > Please view in a fixed-width font such as Courier.
...Jim Thompson
-- | James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
>>John Larkin wrote:
>>> On Sat, 31 Mar 2012 10:11:05 -0700, Joerg <inva...@invalid.invalid>
>>> wrote:
>>>> Rich Webb wrote:
>>>>> On Sat, 31 Mar 2012 09:17:33 +0100, "TTman" <pcw1....@ntlworld.com>
>>>>> wrote:
>>>>>> Can anyone suggest anything ? A 1 amp device with I adj. from 100mA up ...
>>>>>> Does it exist ? >>>>> An LM723 with a pass transistor. I've found it in lots of benchtop
>>>>> supplies with adjustable voltage and current limits. The datasheet has
>>>>> examples for a starting point.
>>>> Bingo!
>>>> That's the way it's done. Lots of linear "bricks" still use that old
>>>> 723. Comes under other prefixes as well, such as uA723. It is one of
>>>> those "forever chips".
>>> I designed a power supply recently, and was surprised that nothing
>>> better than a 723 was available.
>>Yes, it's like the Willys Jeep and the Land Rover. Modern linear
>>regulators are often ill-conceived in that they do not allow access to
>>internal stuff like switcher chips do.
>>You could roll your own using a Cypress PSoC. They have analog building
>>blocks in there and AFAIK are the only affordable analog programmable
>>device out there. It's not against the law to abandon the digital stuff
>>in them but they do cost around a buck or more, which is a problem for
>>many of my cases. The performance of the analog parts is not much to
>>write home about but one can play tricks like automatic offset
>>compensation because the uC in there is now essentially free. Once
>>you've got a design going you could file it away as in-house IP and use
>>it over and over again.
>The problem with "modern" parts like that is (1) all the work you have
>to do to program them and (2) they only work at low voltages and (3)
>they will be obsolete before the 723 is!
In a way it is really cool, the 723 is older than the 555 and still known
to be very useful. Kinda like the uA741 and the LM101 as well.
>> In a way it is really cool, the 723 is older than the 555 and still
>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>As I've intimated before, I've had endless fun (not), getting 723s with
>added pass transistors, to stop oscillating at HF, in other people's
>(commercial) designs.
>The 741 used to latch up.Maybe they've cured that problem in the
>intervening years. I stopped using them as soon as I could.
The 741's that latched were bad copies... the originally published
schematic was of an early botched version, but was never changed...
quick-to-second-source loons missed it ;-)
...Jim Thompson
-- | James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
On Thursday, April 5, 2012 12:32:35 PM UTC-4, Fred Abse wrote:
> On Wed, 04 Apr 2012 19:59:58 -0700, josephkk wrote:
> > In a way it is really cool, the 723 is older than the 555 and still
> > known to be very useful. Kinda like the uA741 and the LM101 as well.
> As I've intimated before, I've had endless fun (not), getting 723s with
> added pass transistors, to stop oscillating at HF, in other people's
> (commercial) designs.
> The 741 used to latch up.Maybe they've cured that problem in the
> intervening years. I stopped using them as soon as I could.
> -- > "For a successful technology, reality must take precedence > over public relations, for nature cannot be fooled."
> (Richard Feynman)
Was that added pass transistor a PNP common emitter? Same problem as with the modern LDOs, you need to know a little bit about phase compensation. There is no stability problem with NPN darlington current boost and the 723.
Fred Abse wrote:
> On Wed, 04 Apr 2012 19:59:58 -0700, josephkk wrote:
>> In a way it is really cool, the 723 is older than the 555 and still
>> known to be very useful. Kinda like the uA741 and the LM101 as well.
> As I've intimated before, I've had endless fun (not), getting 723s with
> added pass transistors, to stop oscillating at HF, in other people's
> (commercial) designs.
Commercial is not a guarantee for good designs. Often the circuit design
is ok but the layout is horrid.
I've never had even a whiff of a problem with the 723, they always worked.
> The 741 used to latch up.Maybe they've cured that problem in the
> intervening years. I stopped using them as soon as I could.
Back in its days discrete designs were often cheaper. So I rarely used
it and if I did need an opamp I preferred the 709. But the bulk of my
designs use the 324, it is much better.
>> In a way it is really cool, the 723 is older than the 555 and still
>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>As I've intimated before, I've had endless fun (not), getting 723s with
>added pass transistors, to stop oscillating at HF, in other people's
>(commercial) designs.
>The 741 used to latch up.Maybe they've cured that problem in the
>intervening years. I stopped using them as soon as I could.
741's were OK. It was the 709 that had bad latchup problems, when one
of the front-end transistors zenered. I remember, as a kid, deciding
to use 741s in systems, instead of 709s. The 741s were a lot more
expensive at the time.
I wonder what's the oldest IC still in production.
Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation
>>> In a way it is really cool, the 723 is older than the 555 and still
>>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>>As I've intimated before, I've had endless fun (not), getting 723s with
>>added pass transistors, to stop oscillating at HF, in other people's
>>(commercial) designs.
>>The 741 used to latch up.Maybe they've cured that problem in the
>>intervening years. I stopped using them as soon as I could.
>741's were OK. It was the 709 that had bad latchup problems, when one
>of the front-end transistors zenered. I remember, as a kid, deciding
>to use 741s in systems, instead of 709s. The 741s were a lot more
>expensive at the time.
>I wonder what's the oldest IC still in production.
Maybe the SN5400/7400 (ca. 1965)- still shows as "active" on TI's
website.
That's approaching the half-century mark, and starting only a few
years after ICs were first commercialized.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
John Larkin wrote:
> On Thu, 05 Apr 2012 09:32:35 -0700, Fred Abse
> <excretatau...@invalid.invalid> wrote:
>> On Wed, 04 Apr 2012 19:59:58 -0700, josephkk wrote:
>>> In a way it is really cool, the 723 is older than the 555 and still
>>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>> As I've intimated before, I've had endless fun (not), getting 723s with
>> added pass transistors, to stop oscillating at HF, in other people's
>> (commercial) designs.
>> The 741 used to latch up.Maybe they've cured that problem in the
>> intervening years. I stopped using them as soon as I could.
> 741's were OK. It was the 709 that had bad latchup problems, when one
> of the front-end transistors zenered. I remember, as a kid, deciding
> to use 741s in systems, instead of 709s. The 741s were a lot more
> expensive at the time.
It's been a bit long ago but I think one reason I liked the 709 better
was because it was not internally compensated so cuold be souped up. Of
course, my class mates only souped up mopeds instead. One of them died
that way :-(
> I wonder what's the oldest IC still in production.
Most likely a military chip where we'll never find out the introduction
date unless it's declassified before we all are six feet under.
>>>> In a way it is really cool, the 723 is older than the 555 and still
>>>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>>>As I've intimated before, I've had endless fun (not), getting 723s with
>>>added pass transistors, to stop oscillating at HF, in other people's
>>>(commercial) designs.
>>>The 741 used to latch up.Maybe they've cured that problem in the
>>>intervening years. I stopped using them as soon as I could.
>>741's were OK. It was the 709 that had bad latchup problems, when one
>>of the front-end transistors zenered. I remember, as a kid, deciding
>>to use 741s in systems, instead of 709s. The 741s were a lot more
>>expensive at the time.
>>I wonder what's the oldest IC still in production.
>Maybe the SN5400/7400 (ca. 1965)- still shows as "active" on TI's
>website.
Sounds like it. The 741 was introduced in 1968, and the 555 in 1971.
On a sunny day (Fri, 06 Apr 2012 19:10:41 -0700) it happened John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote in
<3e8vn713jha1ks6v5i30ie1vd2d0qn6...@4ax.com>:
>>>>> In a way it is really cool, the 723 is older than the 555 and still
>>>>> known to be very useful. Kinda like the uA741 and the LM101 as well.
>>>>As I've intimated before, I've had endless fun (not), getting 723s with
>>>>added pass transistors, to stop oscillating at HF, in other people's
>>>>(commercial) designs.
>>>>The 741 used to latch up.Maybe they've cured that problem in the
>>>>intervening years. I stopped using them as soon as I could.
>>>741's were OK. It was the 709 that had bad latchup problems, when one
>>>of the front-end transistors zenered. I remember, as a kid, deciding
>>>to use 741s in systems, instead of 709s. The 741s were a lot more
>>>expensive at the time.
>>>I wonder what's the oldest IC still in production.
>>Maybe the SN5400/7400 (ca. 1965)- still shows as "active" on TI's
>>website.
>Sounds like it. The 741 was introduced in 1968, and the 555 in 1971.
I made a nice audio mixer with some 741s, liked it much better than the 709,
no need for that compensation capacitor.
I still have some 741s in the box.
