Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: _Moonbot_ on February 16, 2011, 10:31:26 AM
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I'm new to robotics and was wondering if someone could explain Ohm's Law to me. ???
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ohms law basicly shows the relation between resistance, current and voltage. look at the wheel below
(http://img690.imageshack.us/img690/1598/images1kj.jpg) (http://img690.imageshack.us/i/images1kj.jpg/)
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instead of E you can use V for voltage. by shifting arround a the ohms law calculation you can find current, voltage and resistance using any of the other 2 variables. If for instance you have a 1.5v battery with an unknown resistor.
you measure 0.00075 amps. with that info you could find out what the resistor is through the ohms law calculation R=E/I or R=1.5/0.00075. the answer is 2000 meaning you have a 2k resistor!
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Ok, I hope You know Google (http://www.google.co.uk/#sclient=psy&hl=en&q=ohm%27s+law&aq=0s&aqi=g-s1g3g-o1&aql=&oq=&pbx=1&fp=7ebb19a20004984e), try pressing the link ;D
Once I've read a nice explanation of Current, Voltage and Resistance is. It goes something along these lines.
If You compare electricity to Your house water system:
Voltage is a Water Pipe
Current is a Water Flow
Resistance is a Valve(or a tap)
Now, You can imagine that the bigger the Water Pipe the bigger Water Flow is.
Same with electricity, the bigger the Voltage, the more Current You can get.
If You have a Valve(or a tap) You can reduce Water Flow with it because size of the Water Pipe is reduced at that spot (if You get what I mean), hence with Resistance (Resistor) you can reduce Current by creating a Voltage drop at a certain spot in a circuit.
That's what Ohm's Law is about.
I - Current
V - Voltage
R - Resistance
I = V / R
V = I * R
R = V / I
There is a nice free simulation software called Yenka (http://www.yenka.com/en/Download_the_Yenka_installer/) that has loads of useful and interactive examples on basic electronics.
Take care :)
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If You have a Valve(or a tap) You can reduce Water Flow with it because size of the Water Pipe is reduced at that spot (if You get what I mean), hence with Resistance (Resistor) you can reduce Current by creating a Voltage drop at a certain spot in a circuit.
That's not entirely accurate... The voltage drop is the consequence not the form factor... Resistance is the form factor... Or even better applied voltage at a closed circuit is the form factor...
Ohm's law says that the current is analogue to voltage applied in a close circuit of certain resistance... ;-)
That's more obvious if you know about non lineal components like diodes where there is always a voltage drop added to ohmic voltage drop...
Anyways, I'm just saying! That color example was a very nice writing!!! Keep it up mate ;-)
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That's not entirely accurate... The voltage drop is the consequence not the form factor... Resistance is the form factor... Or even better applied voltage at a closed circuit is the form factor...
Yes , You are correct, voltage drop is a consequence of by resistance reduced current; I've expressed myself that way to make it easier to understand the basic concept. ;)
Take care :)
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Hi all,
Anybody know how to convert the LDR OHM NSL 5520 the candela?