> On 2023/03/16 12:15 a.m., Jan Panteltje wrote:
>> On a sunny day (Wed, 15 Mar 2023 12:00:02 -0700) it happened John
>> Robertson
>> <jrr@flippers.com> wrote in <tut4jn$10ok6$1@dont-email.me>:
>>
>>> I'm updating some game board designs and was curious if there is any
>>> sort of printed guideline for replacing silicon driver transistors with
>>> MOS? Both NPN and PNP.
>>>
>>> For example TIP122 Darlington transistors driven by another pre-driver,
>>> that is the TTL interface. I've seen many a substitute, but would like
>>> to have the theory explained so I can make better use of it and
>>> understand exactly what I am doing.
>>>
>>> A good reference book you can recommend perhaps? Books and I usually get
>>> along very well.
>>>
>>> Too many projects and not enough to hunt down all the solutions!
>>>
>>> Thanks, and sorry for the on-topic post...
>>>
>>> John :-#)#
>>
>> This is how MOSFETs work:
>> https://en.wikipedia.org/wiki/MOSFET
>>
>>
>> If you want to use one: there are basically 2 types: some conduct with
>> zero volts at the gate
>> and some do not conduct with zero volts at the gate.
>>
>> To interface with 5V logic I usually use an IRFZ44A MOSFET (off when
>> 0V at the gate).
>> 10 for $8.63 on ebay..
>> https://www.ebay.com/itm/324380901727
>> even cheaper at other places
>> datasheet:
>> https://datasheetspdf.com/pdf-file/799031/Samsung/IRFZ44A/1
>>
>> look at page 3 figure 2 for at what voltage the thing starts conducting.
>>
>> At 5 V from TTL logic it can do several amps.
>> MOSFETS do not pose a current drain on the driver (very high
>> impedance, these should work for a pinball machine I'd think).
>> Also these MOSFETS have a reverse diode that limits the peak voltages
>> when switching an inductive load,
>> see figure 13 in that datasheet (may save you a protection diode, but
>> of course you can leave it in too).
>>
>> So this is a "simple practicle man's few lines book" but you gotta
>> start somewhere...
>>
>> More in my book 'The Fart Of Electronics' provided I ever can find a
>> decent pen to write it.
>>
>> There also exists a book 'The art of electronics' I'v never read it
>> but people get all exited about it it seems.
>> The author used to post here...
>
> I've been meaning to buy Winfield (& Horowitz)'s book for a while, and
> now you have tipped the balance. I'm sure that will be a useful addition
> to my library!
>
> Thanks!
>
> John :-#)#
Ordered the hard cover - 2015 3rd edition - (I prefer books) and also
picked up the PDF from Academia.edu.
Wow! What can I say other than this is the book I've needed my whole
career! To say it goes into detail but in plain enough language for a
non formally (EET) student like me to understand.
Now I think I will have to get the X Chapters (2020) that Winfield spoke
of here, after reading the 3rd edition first.
I'm sorry Mr. Hill no longer posts here, he was a great reference and I
think he enjoyed interacting with the folks here that are actually
interested in learning about electronics and sharing their knowledge.
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Reply by John Robertson●March 17, 20232023-03-17
On 2023/03/16 12:15 a.m., Jan Panteltje wrote:
> On a sunny day (Wed, 15 Mar 2023 12:00:02 -0700) it happened John Robertson
> <jrr@flippers.com> wrote in <tut4jn$10ok6$1@dont-email.me>:
>
>> I'm updating some game board designs and was curious if there is any
>> sort of printed guideline for replacing silicon driver transistors with
>> MOS? Both NPN and PNP.
>>
>> For example TIP122 Darlington transistors driven by another pre-driver,
>> that is the TTL interface. I've seen many a substitute, but would like
>> to have the theory explained so I can make better use of it and
>> understand exactly what I am doing.
>>
>> A good reference book you can recommend perhaps? Books and I usually get
>> along very well.
>>
>> Too many projects and not enough to hunt down all the solutions!
>>
>> Thanks, and sorry for the on-topic post...
>>
>> John :-#)#
>
> This is how MOSFETs work:
> https://en.wikipedia.org/wiki/MOSFET
>
>
> If you want to use one: there are basically 2 types: some conduct with zero volts at the gate
> and some do not conduct with zero volts at the gate.
>
> To interface with 5V logic I usually use an IRFZ44A MOSFET (off when 0V at the gate).
> 10 for $8.63 on ebay..
> https://www.ebay.com/itm/324380901727
> even cheaper at other places
> datasheet:
> https://datasheetspdf.com/pdf-file/799031/Samsung/IRFZ44A/1
>
> look at page 3 figure 2 for at what voltage the thing starts conducting.
>
> At 5 V from TTL logic it can do several amps.
> MOSFETS do not pose a current drain on the driver (very high impedance, these should work for a pinball machine I'd think).
> Also these MOSFETS have a reverse diode that limits the peak voltages when switching an inductive load,
> see figure 13 in that datasheet (may save you a protection diode, but of course you can leave it in too).
>
> So this is a "simple practicle man's few lines book" but you gotta start somewhere...
>
> More in my book 'The Fart Of Electronics' provided I ever can find a decent pen to write it.
>
> There also exists a book 'The art of electronics' I'v never read it but people get all exited about it it seems.
> The author used to post here...
I've been meaning to buy Winfield (& Horowitz)'s book for a while, and
now you have tipped the balance. I'm sure that will be a useful addition
to my library!
Thanks!
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
#7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Reply by John Larkin●March 17, 20232023-03-17
On Fri, 17 Mar 2023 04:59:22 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:
>On Thursday, March 16, 2023 at 12:16:14?PM UTC-4, John Larkin wrote:
>> On Thu, 16 Mar 2023 05:06:35 -0700 (PDT), Fred Bloggs
>> <bloggs.fred...@gmail.com> wrote:
>> >On Wednesday, March 15, 2023 at 3:00:19?PM UTC-4, John Robertson wrote:
>> >> I'm updating some game board designs and was curious if there is any
>> >> sort of printed guideline for replacing silicon driver transistors with
>> >> MOS? Both NPN and PNP.
>> >>
>> >> For example TIP122 Darlington transistors driven by another pre-driver,
>> >> that is the TTL interface. I've seen many a substitute, but would like
>> >> to have the theory explained so I can make better use of it and
>> >> understand exactly what I am doing.
>> >>
>> >> A good reference book you can recommend perhaps? Books and I usually get
>> >> along very well.
>> >>
>> >> Too many projects and not enough to hunt down all the solutions!
>> >
>> >Unless there's an availability problem with the bipolar, leave it. As far as any rules of thumb: don't touch a hot case with your bare thumb.
>> >
>> >>
>> >> Thanks, and sorry for the on-topic post...
>> >
>> >You're one of these whiners always complaining about the group content, while contributing little to nothing yourself.
>> >
>> Never miss the opportunity to redirect a technical thread to an insult
>> fest.
>
>Fet is not a word, it's an acronym, so it's not MOSFet, it's MOSFET. Post is off topic, because it doesn't have much to do with design, it belongs is sci basic basics.
FET is a fetish to whine about grammarschoolmarm rules. A 2N7002
doesn't care what you call it.
What's the last thing you designed with mosfets?
Reply by legg●March 17, 20232023-03-17
On Wed, 15 Mar 2023 12:00:02 -0700, John Robertson <jrr@flippers.com>
wrote:
>I'm updating some game board designs and was curious if there is any
>sort of printed guideline for replacing silicon driver transistors with
>MOS? Both NPN and PNP.
>
>For example TIP122 Darlington transistors driven by another pre-driver,
>that is the TTL interface. I've seen many a substitute, but would like
>to have the theory explained so I can make better use of it and
>understand exactly what I am doing.
>
>A good reference book you can recommend perhaps? Books and I usually get
>along very well.
>
>Too many projects and not enough to hunt down all the solutions!
>
>Thanks, and sorry for the on-topic post...
>
>John :-#)#
Given sufficient voltage in the gate drive, just make sure RdsxIds is
less than the old Vcesat that was present.
I used to stick fets in older bipolar SMPS and could usually increase
unit rating till something else in the power train started to sweat.
Often a magnetic part.
RL
Reply by Fred Bloggs●March 17, 20232023-03-17
On Thursday, March 16, 2023 at 9:28:43 AM UTC-4, legg wrote:
> On Thu, 16 Mar 2023 05:06:35 -0700 (PDT), Fred Bloggs
> <bloggs.fred...@gmail.com> wrote:
> >On Wednesday, March 15, 2023 at 3:00:19?PM UTC-4, John Robertson wrote:
> >> I'm updating some game board designs and was curious if there is any
> >> sort of printed guideline for replacing silicon driver transistors with
> >> MOS? Both NPN and PNP.
> >>
> >> For example TIP122 Darlington transistors driven by another pre-driver,
> >> that is the TTL interface. I've seen many a substitute, but would like
> >> to have the theory explained so I can make better use of it and
> >> understand exactly what I am doing.
> >>
> >> A good reference book you can recommend perhaps? Books and I usually get
> >> along very well.
> >>
> >> Too many projects and not enough to hunt down all the solutions!
> >
> >Unless there's an availability problem with the bipolar, leave it. As far as any rules of thumb: don't touch a hot case with your bare thumb.
> >
> >>
> >> Thanks, and sorry for the on-topic post...
> >
> >You're one of these whiners always complaining about the group content, while contributing little to nothing yourself.
> >
> >>
> >> John :-#)#
> Hey, your kettle's black.
>
> Just deleted at least ten of your most recent posts as being OT.
Ask me if I give a damn.
>
> RL
Reply by Fred Bloggs●March 17, 20232023-03-17
On Thursday, March 16, 2023 at 4:39:52 PM UTC-4, Anthony Stewart wrote:
> All FETS have 50% threshold tolerance on gate voltage and those std types with Vt= 2 to 4V need at least 250% times the actual threshold to make a good switch.
>
> Although BJT transistors have a vast range in hFE, however when used as a switch, it is the actual Vbe that controls the current. Normally they are typically rated as switches with base current = 10% of Ic unless they are super beta types hFE> 300.
The external circuit determines the current in a transistor switching application. The design merely ensures the base drive current is sufficient to support that current worst case, while keeping it to a minimum..
>
> The critical power dissipation in switches is the ON resistance, such as Vce(sat)/Ic=Rce and RdsOn @ Vgs.
>
> But the secret in fast pinball bumpers is the low T=L/R.
> That means lower inductance and higher resistance but hotter or less efficient but faster.
> This is important for spring back solenoid bumpers and flippers.
> Dry contact switches produce very high back EMF so a clamp diode is needed but this slows the L/R=T time even with a stiff spring. So instead of a diode clamp by adding a Zener & diode in series makes it faster and limits the maximum voltage for the switch for safety.
>
> As far as substitutions, one needs to know the load, current, voltage and function. Otherwise, why would they stock seventy-five thousand different FETs.
>
> It's a matter of the heatsink method, size, cost, drive voltage, load current, availability, and compatibility. Copying newer designs can help.
Reply by Fred Bloggs●March 17, 20232023-03-17
On Thursday, March 16, 2023 at 12:16:14 PM UTC-4, John Larkin wrote:
> On Thu, 16 Mar 2023 05:06:35 -0700 (PDT), Fred Bloggs
> <bloggs.fred...@gmail.com> wrote:
> >On Wednesday, March 15, 2023 at 3:00:19?PM UTC-4, John Robertson wrote:
> >> I'm updating some game board designs and was curious if there is any
> >> sort of printed guideline for replacing silicon driver transistors with
> >> MOS? Both NPN and PNP.
> >>
> >> For example TIP122 Darlington transistors driven by another pre-driver,
> >> that is the TTL interface. I've seen many a substitute, but would like
> >> to have the theory explained so I can make better use of it and
> >> understand exactly what I am doing.
> >>
> >> A good reference book you can recommend perhaps? Books and I usually get
> >> along very well.
> >>
> >> Too many projects and not enough to hunt down all the solutions!
> >
> >Unless there's an availability problem with the bipolar, leave it. As far as any rules of thumb: don't touch a hot case with your bare thumb.
> >
> >>
> >> Thanks, and sorry for the on-topic post...
> >
> >You're one of these whiners always complaining about the group content, while contributing little to nothing yourself.
> >
> Never miss the opportunity to redirect a technical thread to an insult
> fest.
Fet is not a word, it's an acronym, so it's not MOSFet, it's MOSFET. Post is off topic, because it doesn't have much to do with design, it belongs is sci basic basics.
Reply by John Larkin●March 17, 20232023-03-17
On Fri, 17 Mar 2023 06:32:57 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
>On a sunny day (Thu, 16 Mar 2023 09:13:58 -0700) it happened John Larkin
><jlarkin@highlandSNIPMEtechnology.com> wrote in
><5vf61i137r720gkme27pk26j93pp8so6cs@4ax.com>:
>
>>On Thu, 16 Mar 2023 07:15:30 GMT, Jan Panteltje <alien@comet.invalid>
>>wrote:
>>
>>>On a sunny day (Wed, 15 Mar 2023 12:00:02 -0700) it happened John Robertson
>>><jrr@flippers.com> wrote in <tut4jn$10ok6$1@dont-email.me>:
>>>
>>>>I'm updating some game board designs and was curious if there is any
>>>>sort of printed guideline for replacing silicon driver transistors with
>>>>MOS? Both NPN and PNP.
>>>>
>>>>For example TIP122 Darlington transistors driven by another pre-driver,
>>>>that is the TTL interface. I've seen many a substitute, but would like
>>>>to have the theory explained so I can make better use of it and
>>>>understand exactly what I am doing.
>>>>
>>>>A good reference book you can recommend perhaps? Books and I usually get
>>>>along very well.
>>>>
>>>>Too many projects and not enough to hunt down all the solutions!
>>>>
>>>>Thanks, and sorry for the on-topic post...
>>>>
>>>>John :-#)#
>>>
>>>This is how MOSFETs work:
>>>https://en.wikipedia.org/wiki/MOSFET
>>>
>>>
>>>If you want to use one: there are basically 2 types: some conduct with zero volts at the gate
>>>and some do not conduct with zero volts at the gate.
>>>
>>>To interface with 5V logic I usually use an IRFZ44A MOSFET (off when 0V at the gate).
>>>10 for $8.63 on ebay..
>>> https://www.ebay.com/itm/324380901727
>>>even cheaper at other places
>>>datasheet:
>>> https://datasheetspdf.com/pdf-file/799031/Samsung/IRFZ44A/1
>>>
>>>look at page 3 figure 2 for at what voltage the thing starts conducting.
>>>
>>>At 5 V from TTL logic it can do several amps.
>>
>>Note that 74-series TTL does not pull up to 5 volts.
>
>Yes, but even at 4.5 V gate that IRFZ44A does 10 A
Add a pullup, or substitute an HCT part.
Reply by Jan Panteltje●March 17, 20232023-03-17
On a sunny day (Thu, 16 Mar 2023 09:13:58 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<5vf61i137r720gkme27pk26j93pp8so6cs@4ax.com>:
>On Thu, 16 Mar 2023 07:15:30 GMT, Jan Panteltje <alien@comet.invalid>
>wrote:
>
>>On a sunny day (Wed, 15 Mar 2023 12:00:02 -0700) it happened John Robertson
>><jrr@flippers.com> wrote in <tut4jn$10ok6$1@dont-email.me>:
>>
>>>I'm updating some game board designs and was curious if there is any
>>>sort of printed guideline for replacing silicon driver transistors with
>>>MOS? Both NPN and PNP.
>>>
>>>For example TIP122 Darlington transistors driven by another pre-driver,
>>>that is the TTL interface. I've seen many a substitute, but would like
>>>to have the theory explained so I can make better use of it and
>>>understand exactly what I am doing.
>>>
>>>A good reference book you can recommend perhaps? Books and I usually get
>>>along very well.
>>>
>>>Too many projects and not enough to hunt down all the solutions!
>>>
>>>Thanks, and sorry for the on-topic post...
>>>
>>>John :-#)#
>>
>>This is how MOSFETs work:
>>https://en.wikipedia.org/wiki/MOSFET
>>
>>
>>If you want to use one: there are basically 2 types: some conduct with zero volts at the gate
>>and some do not conduct with zero volts at the gate.
>>
>>To interface with 5V logic I usually use an IRFZ44A MOSFET (off when 0V at the gate).
>>10 for $8.63 on ebay..
>> https://www.ebay.com/itm/324380901727
>>even cheaper at other places
>>datasheet:
>> https://datasheetspdf.com/pdf-file/799031/Samsung/IRFZ44A/1
>>
>>look at page 3 figure 2 for at what voltage the thing starts conducting.
>>
>>At 5 V from TTL logic it can do several amps.
>
>Note that 74-series TTL does not pull up to 5 volts.
Yes, but even at 4.5 V gate that IRFZ44A does 10 A
Reply by piglet●March 16, 20232023-03-16
On 15/03/2023 7:00 pm, John Robertson wrote:
> I'm updating some game board designs and was curious if there is any
> sort of printed guideline for replacing silicon driver transistors with
> MOS? Both NPN and PNP.
>
> For example TIP122 Darlington transistors driven by another pre-driver,
> that is the TTL interface. I've seen many a substitute, but would like
> to have the theory explained so I can make better use of it and
> understand exactly what I am doing.
>
> A good reference book you can recommend perhaps? Books and I usually get
> along very well.
>
> Too many projects and not enough to hunt down all the solutions!
>
> Thanks, and sorry for the on-topic post...
>
> John :-#)#
>
Can you say what kind of loads they are switching and at what rates?
piglet