How to Use a Sperry Digital Multimeter DM-350A
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The Sperry DM-350A multimeter is a compact and safe digital model that allows you to take electrical measurements at home or in an industrial setting. the multimeter can take readings of up to 600 volts, 200 milliamps and 20 million ohms.
Most circuits you will encounter will fall far below these ranges, so there is little danger of overloading your multimeter. The multimeter is also capable of measuring multiple ranges for each function depending on the strength of the circuit.
Set the dial on the multimeter to the highest range in the measurement you want to take. The dial is divided into four sections. DC voltage is located at top left, AC voltage at the top right, current at lower left and resistance/continuity at lower right.
Plug the test leads into their appropriate sockets. For voltage and resistance/diode tests, insert the red lead into the "V" and "Ω" sockets respectively. For current measurements, put it into the "A" socket. The black lead always goes into the "COM" socket.
Test voltage by touching the two leads to contact points on a powered circuit. Test resistance by removing power from the circuit and touching the leads to contact points. Test current flow by turning off the circuit, putting the multimeter in series with it -- making it part of the circuit -- and restoring power, then turning off power and removing the meter.
Remove the leads from the multimeter and store them in a safe place.
- Never attempt to use the multimeter if the casing is cracked or if any wires are frayed. The casing provides insulation from electrical current. Always start with the highest measurement range, and never attempt to measure circuits if you think their measurement may be too high.
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