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Standard parts values? - Parts library.

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Zero999:

--- Quote from: Varal on September 06, 2010, 10:55:14 pm ---don't get carried away with those cristalls - microcontrollers aren't cheap so why bother to level up a project's cost? Plus the internal oscillators (1MHz for avr dunno about PIC) will suit most of a beginners needs
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Corrected.


--- Quote ---don't stock up on electrolytic caps - they may dry over time and the operating voltage differs much (no use of a 25 volt cap when powering a 40 volt audio amp)
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I've heard about this but I've never experienced it myself with capacitors in storage, only in service.

In short I disagree, it's always good to have a supply of the most commonly used electrolytic capacitors and as far as working voltage is concerned: you can always use a higher voltage rated capacitor at a lower voltage i.e. a 50V capacitor in a 12V application.

It's probably a good idea to at least keep all the decade values from 1µF to 1000µF, possibly even 10,000µF  if you build high current power supplies. If you have the E3 values from 1µF to 10,000µF you'll be covered for 90% of cases, the E6 series will cover you for 99% of cases. For the smaller capacitors (?100µF), there's no need to get any voltage under 50V because they're so cheap, for the larger capacitors you might be constrained to lower voltages due to budget limitations but it depends on what you're doing, it's better to get more expensive components, as and when you need them anyway.


--- Quote ---also don't stock on integrated circuits like TTL's and CMOS - they're not always used and there are many ways to solve problems using different chips
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True to some extent but I've found some basic logic gates to be very handy, although I agree it's questionable whether one should want loads of them in their inventory.

CMOS and HC quad NAND/NOR/NOT gates i.e. CD4001/4011/4069 and 74HC00/02/08 have numerous uses from oscillators and timers to even linear amplifiers/analogue comparators and are certainly more useful than crappy components such as the 555 timer or 741 op-amp, I know you didn't suggest these but many people do.

Other useful CMOS ICs include:
CD4013, 74HC74 -  dual flip-flop, useful for building timers, oscillators and a basic on-off switch.
74HC14 - hex Schmitt trigger inverter, useful for oscillator/timers and de-bouncing switches.
74HC/CD4017 - a decade counter with 10 decoded outputs: can be used for multiplexing switches/displays with an MCU - have 10 switches connected to just three MCU pins!
CD4007 - some MOSFETs, nothing great but they're all on the same IC which means they're matched which can be useful for analogue applications.
74HC/CD4046 - a cheap phase-lock-loop which can be used as a tone detector (better than the NE567) .

Analogue switches and multiplexers:
CD/74HC4066 - a cheap analogue switch, the 74HC version has a lower maximum operating voltage but much lower resistance, useful for switching components in and out of feedback loops.
CD/74HC4067 - a cheap analogue multiplexer.
CD/74HC4097 - as above but differential.
 
I'd also recommend some comparator ICs, although they're integrated into MCUS nowadays, they're still useful for simple circuits where an MCU isn't worth it.
LM311 - a single comparator with am output capable of driving up to 50mA meaning it can directly drive a small relay.
LM393 - a dual comparator.
LM339 - a quad version of the above.

Single supply op-amps:
LM324 quad
LM358 dual
I know they're better ICs than the above but they're cheap/easy to get hold of and are still useful.

Varal:
Hero999 the correction you've made isn't valid for Poland - Atmel had a problem with continuous supply of their chips so the prices in my local electronics stores have doubled. :) Big players like Farnell also have high prices atm :)

Simon:
prices for MCU's will vary and will be more expensive than old fashioned IC's you can get a 555 timer cheaper than the 12F pics like the 609, 615, 675 and others and stuff like comparators are much cheaper than MCU's of course if you use an MCU to replace a whole load of circuitry yea it's cheaper but then thats not building up a stock of generic parts as you just replaced them all with an MCU

Zero999:

--- Quote from: Varal on September 07, 2010, 07:12:04 pm ---Hero999 the correction you've made isn't valid for Poland - Atmel had a problem with continuous supply of their chips so the prices in my local electronics stores have doubled. :) Big players like Farnell also have high prices atm :)

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Simple, go with Microchip, their parts still seem to be reasonably priced, the cheapest MCU I could find the 12F508 which is what one would use to emulate a few 555s or logic gate ICs and costs just 57p from Farnel.
http://uk.farnell.com/microchip/pic12f508-i-p/8bit-flash-mcu-12f508-dip8/dp/1123006


--- Quote from: Simon on September 07, 2010, 09:38:15 pm ---prices for MCU's will vary and will be more expensive than old fashioned IC's you can get a 555 timer cheaper than the 12F pics like the 609, 615, 675 and others and stuff like comparators are much cheaper than MCU's of course if you use an MCU to replace a whole load of circuitry yea it's cheaper but then thats not building up a stock of generic parts as you just replaced them all with an MCU

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I suppose MCUs have other disadvantages such as the maximum supply voltage of only 5.5V and limited output drive which means other components such as voltage regulators and driver transistors are often necessary.

Nevertheless isn't it still more convenient to have a stock of more generic parts rather than many different parts?




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