Changes between Version 25 and Version 26 of ElectricalIntroduction

Timestamp:

Aug 26, 2017, 2:20:05 PM (8 years ago)

Author:

David Albert

Comment:

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ElectricalIntroduction

@@ -27 +27 @@
 
 [[Image(static_shock.jpg, left, 10%)]]
-Different [http://www.houseofbatteries.com/battery-chemistry-chart-i-52-l-en.html battery chemistries] generate different voltage potentials.  For example, NiMH rechargeable batteries create about 1.2 volts, alkaline disposable batteries create about 1.5 volts, lead-acid rechargeable batteries create about 2 volts, and lithium batteries create 3-3.7 volts.  You can connect batteries in sequence to increase the difference in charge (voltage) between the battery terminal at the start of the sequence and the battery terminal at the end; this is called placing the batteries in ''series''.  By placing 6 lead-acid cells in series you can make a 12V battery (which is what we use for robots).  When you buy a 12v SLA battery, it really contains 6 individual 2V cells in one package.  The lead-acid battery is the oldest type of battery, and is the one we still use on our robots, lead-acid batteries have lead terminals and sulphuric acid electrolyte.  
+Different [http://www.houseofbatteries.com/battery-chemistry-chart-i-52-l-en.html battery chemistries] generate different voltage potentials.  For example, NiMH rechargeable batteries create about 1.2 volts, alkaline disposable batteries create about 1.5 volts, lead-acid rechargeable cells create about 2 volts, and lithium batteries create 3-3.7 volts.  You can connect batteries in sequence (series) to increase the difference in charge (voltage) between the battery terminal at the start of the sequence and the battery terminal at the end; this is called placing the batteries in ''series''.  By placing 6 lead-acid cells in series you can make a 12V battery (which is what we use for robots).  When you buy a 12v SLA battery, it really contains 6 individual 2V cells in one package.  The lead-acid battery is the oldest type of battery, and is the one we still use on our robots, lead-acid batteries have lead terminals and sulphuric acid electrolyte.  
 
 * When you get a static shock, such as touching a doorknob in the winter, you are feeling thousands of volts! 
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 == Multimeter ==
-You can use a meter called a voltmeter or a [multimeter to measure the amount of voltage "pressure" a battery exerts.  Multimeters are inexpensive ($[https://www.harborfreight.com/7-function-multimeter-98025.html 5] - [https://www.amazon.com/UNI-T-Digital-Multimeter-Frequency-Resistance/dp/B00AW6SHNO 25]) and incredibly useful; every house should have at least one and every robotics student and mentor should be comfortable using a multimeter.  More expensive meters can usually measure more things and require fewer manual steps.  For example, some multimeters require that you select a range of voltages to measure such as 2V, 20V, 200V, etc. whereas other multimeters will automatically select the proper measurement range (called ''auto-ranging'' meters).  To learn how to use a multimeter, see [https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter this tutorial].  We'll use multimeters in the next few exercises.
+You can use a meter called a multimeter to measure the amount of voltage "pressure" a battery exerts.  Multimeters are inexpensive ($[https://www.harborfreight.com/7-function-multimeter-98025.html 5] - [https://www.amazon.com/UNI-T-Digital-Multimeter-Frequency-Resistance/dp/B00AW6SHNO 25]) and incredibly useful; every house should have at least one and every robotics student and mentor should be comfortable using a multimeter.  More expensive meters can usually measure more things and require fewer manual steps.  For example, some multimeters require that you select a range of voltages to measure such as 2V, 20V, 200V, etc. whereas other multimeters will automatically select the proper measurement range (called ''auto-ranging'' meters).  To learn how to use a multimeter, see [https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter this tutorial].  We'll use multimeters in the next few exercises.
 
 Multimeters include two wires called [https://thelashop.com/products/1-pair-universal-multimeter-test-leads-probes-set?variant=45194996874 leads] which are used to connect the meter to whatever it is measuring.  The leads can usually be unplugged from the meter for replacement, easier storage, and sometimes for making special measurements.  Leads come in different lengths and terminations to make it easy to take different kinds of measurements.  Most leads end in a pencil-style probe with a sharp tip to allow you to probe small electrical contacts precisely.  Other leads have spring-loaded toothy clips at the end called [http://mklec.com/tools/testing-probes-clips-connectors/alligator-clip-multimeter-test-leads-probe-set alligator clips] that make it easy to clip them on to wires or terminals and leave your hands free to do other things.