On 2023/03/17 9:41 a.m., John Robertson wrote:> 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."
Rule of thumb for replacing power transistors with MOSFets?
Started by ●March 15, 2023
Reply by ●March 17, 20232023-03-17
