# Application Of Logic Gates?

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#### Electroenthusiast

##### Member
How exactly can you apply Knowledge of Logic Gates in Electronic Switching?
What are the components used and how are the Connections Made?

Is it same as Microcontroller?

#### georgetwo

##### Member
generally, logic gates are used for making decisions. with logic gates like and not or nand nor etc . you can tell the emergency light to turn on when there is interruption in power suply and it will only turn on at night. the output or gates is always 0 or 1. google has not stopped working

#### Electroenthusiast

##### Member
generally, logic gates are used for making decisions. with logic gates like and not or nand nor etc . you can tell the emergency light to turn on when there is interruption in power suply and it will only turn on at night. the output or gates is always 0 or 1. google has not stopped working

google is working.....but i didn get a circuit diagram for it there !
So...i require a circuit Diag. and i want to know how the IC is applied there!

#### MrDEB

##### Well-Known Member

it should explain everything
Logic Gates
google works, just need to input right search criteria

#### Boncuk

##### New Member
Here is a summary of the logic gates (ANSI and DIN symbols) and their truth tables.

Logic gates don't make a computer. If they are wired logically they make one.

Boncuk

#### Attachments

• Logic_ gates.pdf
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#### codywookman

##### New Member
A very basic computer at that. If you are planning to build a complex project, say more than 5-6 logic gates, I would switch to a microcontroller with programming software that will save you lots of time.

#### Electroenthusiast

##### Member
Here is a summary of the logic gates (ANSI and DIN symbols) and their truth tables.

Logic gates don't make a computer. If they are wired logically they make one.

Boncuk

Thanks...But, i was looking for the connections that has to be made!
Input & Output (Circuit should be complete?)
Is this Circuit Correct? (Basic Switching circuit)

Blue Lines indicate, wires without connections in between.
BAT, Switches are represented in Diag.

#### Attachments

• electro(LD).JPG
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#### MrDEB

##### Well-Known Member
what EXACTLY are you wanting to do??

for one thing if you connect the circuit as pictured, you will smoke the 7404 as it won't drive an incandescent bulb unless it draws less than 20ma.

#### Boncuk

##### New Member
According to the logic of an XOR-gate (7486) the output of that is only high if one input is high and the other low. If both inputs are low or high the output will be low.

Since you are not switching any pin to low that circuit won't work at all up to that point.

Connecting an inverter (7404) to the output of the XOR that one won't have to switch anything since you always have one input of the 7486 floating.

Connecting either a SPDT or pulldown resistors (use 470Ω for TTL logic and 10K for CMOS logic ICs) at the inputs of the 7486 the inputs always have defined state.

Anyway, connecting an inverter to the output of an XOR makes no logical sense to me.

TTL-ICs normally have a fanout of 10, but they won't drive a filament type lamp.

To speak similar to the other post you'll have the impression being surrounded by Indians when connecting a lamp to the IC.

Logic ICs only do the logic work. For the power stages you must direct the output of the logic into a an appropriate power stage.

Here is your intended circuit with two "improvements".

#### Attachments

• XOR.gif
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#### MrDEB

##### Well-Known Member
INDIANS!! thats a good one

you owe me a new monitor Boncuk---lol
smoke siginals for sure connecting a filament lamp to output.
I love your analogy, original for sure.
curious as to what the op wants to build??
if they are just starting in electronics and want to learn about logic, I suggest the TTL cookbook or maybe the cmos cookbook.
check with Abebooks.com

#### Boncuk

##### New Member
you owe me a new monitor Boncuk---lol

Please draw the schematic of the circuit having blown up your monitor.

I'm looking for one blowing the sound card. Thai doodle, rap and heavy machine guns go a bit beyond my nerves' capabilities. Do you have one handy?

#### MrDEB

##### Well-Known Member
just get earplugs--lol

where are you? located??
and what is Thai doodle
some new micro controller programming code-lol

#### Boncuk

##### New Member
where are you? located??

Self explanatory if you look on the L/H side of my posts. Actually I'm German but I have settled in Thailand.
It's easier to get along with authorities for a few Thai Baht than it is in Germany with millions of Euro.

and what is Thai doodle

Thai should be clear. "Doodle" is my word creation describing music causing headaches. It's derived from the German language "Gedudel".

Arabs are champions in "Doodle music".

some new micro controller programming code-lol

I wish I could program MCUs. Just started with Swordfish Basic, but unfortunately I haven't found a summary of Basic key words and their functions yet, e.g. known from GW-Basic <left$((A$),3)>, where A\$ is a variable. If it were "MrDEB" the result would be "MrD", very useful when formatting text outputs.

Boncuk

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#### MrDEB

##### Well-Known Member
I myself am getting into PIC programming

started w/ swordfish. pretty easy compared to other codes.
in the micro controller section of this site the people are very helpful.
good luck

#### Electroenthusiast

##### Member
for one thing if you connect the circuit as pictured, you will smoke the 7404 as it won't drive an incandescent bulb unless it draws less than 20ma.
thnks for the reply...its jus a part of my application in a project...
wat i need to do is a water leeevel controlr using the logic...
Hope u understood?!!!

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