Basic Intro to Electricity
Voltage
Current
Resistence
Never create a short circuit. = Electricity will flow from the positive to the negetive insanely fast and fry the wire.
Voltage = pressure. Of a battery = 1.5V == the pressure difference from the positive to negetive. Measured with a voltmeter. Voltage also = potential difference.
Current is a measure of the amount of electricity that is flowing. (symbol = i)
The unit of current is the Amp.
Resistence = a measure of how well it resists the flow of electricity. Resistence is measured in Ohms. 100 ohms is about the same as a 60W lightbulb. In electronics, we mostly deal in 1Kohms or 10Kohms. The Resistence of a human (Rh) is roughly 1Mohm (1 mega ohm).
Voltage = 1.5V
I at 100ohms = X
I at 1Kohms = Y
X>Y
Ohms Law, V= IR where V = Volts, I = Amps, R = Ohms.
Voltage across something, current through it.
In electronics we deal with milliamps. mA.
Simple sensor circuit is created with 5V and two resistors. Each at 10Kohms.
Two 10Kohm resisters in series create a total resistence of 20Kohms. Rtotal = R1 + R2.
note
Current remains the same throughout a circuit, but the voltage drops through resisters.
Rt = 20Kohms, V = 5, V =IR => I = V/R = 5/20000 = 0.25mA.
Notes at http://seattlerobotics.org/guide/electronics.html
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