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Logic Gates

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first of all, most of the things i got here are from other sites. i just put it here so u can easily get 'em.

but, of course, i will set links to the various pages i got them from.

for the beginner, a few reminders:

check the power! never touch energized, exposed circuit boards even if its "just" 5V. Remember, it isn't the voltage that actually kills, it's the current. sometimes even if it ain't plugged in, it could still be dangerous. check for capacitors. especially the large ones. discharge it first by shorting the leads of the capacitor with a screwdriver. if yer dealing with the big boys (like in TV's and high power circuits) forget it. it's not worth it!
have a "relatively" organized work area. have good lighting and a comfortable seat. if possible, isolate your 220V line going 2 yer area by buying a good supply strip with a built in fuse. watch your soldering iron.. carefully. make a pilot lamp/switch/temp control so u know if its on or not and how hot it can go.
invest on some good test instruments (go Digital VOM if u can shell out a few thousand pesos) and regulated power supplies. for CoE pipol, u basically need a 5V and/or 12 V regulated psu.
Learn how to use the Analog or Digital VOM effectively. Read and undestand the manual carefully and by heart.
PRESENCE OF MIND!!! think before u act. u might save some time and money doing so. ask not to be disturbed once in a while (no BF's or GF's while working).
Power is measured in mW, W, watts and is equal to Voltage * Current; (P=I*V). Current is measured in mA, milliAmperes. Voltage in V or mV, whichever applies. Please be consistent with ur units. kasi 'pag pinaghalo mo ang different units u might ge the wrong answer.

NOW LET'S BUILD SOMETHING!!!

yer first PSU (power supply unit)

naku!!! tandaan lang ang ohm's law ha!! V=I*R once u know and understand this, its smooth sailing. Just to remind u, if u choose to have a high amp rating transformer and add a few more capacitors, please put a good heatsink for your 7805.

parts:

(1) 7805- regulator IC
(2) 0.1 micro farad capacitor, mylar, any volt
(1) 12v or 6v center-tapped transformer, any amp rating will do
(1) 2,200 micro farad capacitor, electrolytic, 25v
(1) W02M or W04M bridge rectifier

TTL and CMOS logic families

what the heck is this?

TTL stands for Transistor to Transistor Logic while CMOS is Complementary Metal-Oxide Semiconductor. this the most basic components that we will b using. when using the CD4xxx or 74xxxxx it is preferable to have a well filtered, regulated, PSU. the CMOS or CD4xxx family has a very good speed and input voltage factor. u can actually use 3-15 volts for the Vcc. this is not possible for theTTL or 74xxxxx series. TTL's require a Vin of 4.5-5.5 volts and consumes more power, around 1.3 mW, compared to the CMOS's 0.7mW power consumption rating. but the main advantage of the TTL is it's high drive current of 8mA; 1-4mA lang ang sa CMOS. it's okei lang to mix and match kasi there may be specific needs of ur design. kaya lang dapat experiment ka muna to acheve the best results.

TIP: it is a good habit to put small ceramic capacitors across the supply leads close to the IC's. especially if ur driving a lot of logic gates. a lot of noise is created by the high speed switching of the logic gates, flip-flops, and this might lead to fatal errors in ur design.

Table of the 74LSxx Logic family

Pin Configs of most of the 74LSxx Logic family

the MPU

pagdating ng araw gagawa ka nito! gagamitin mo din 'to sa DESPRO mo!! kaya galingan mo and good luck!!

MPU