CHAPTER 4 ■ DIGITAL MULTIMETERDigits
3½ digits means that numbers up to 1999 can be displayed (with a floating decimal point). 3 ¾ digits means
that numbers up to 4999 can be displayed. 4 digits means that numbers up to 9999 can be displayed. In
practice, 3½ digits are all that’s needed. Every digital multimeter meets this requirement.
DC Voltage
Measured in volts, DC voltage indicates how much pressure or force the electricity has. A range of 0.2 V (200 mV)
to 48 V is usually all that’s needed for tabletop robots. Every basic multimeter meets this requirement.
DC Current
Measured in amps, DC current indicates how many electrons are speeding by per second. A range of 0.0002 A
(200 mA) to 2 A is usually all that’s needed. Every basic multimeter meets this requirement.
Resistance
Measured in ohms, resistance indicates how much something opposes electricity going through it. A range
of 1 W to 2,000,000 W (2 MW) is usually all that’s needed. Every basic multimeter meets this requirement.
Probes or Leads
The meter should come with the cables (see Figure 4-4) needed to connect it to the parts to test. Every
basic multimeter meets this requirement. Ironically, really expensive pieces of equipment, such as many
oscilloscopes, may require probes that are sold separately.
Figure 4-4. Test probes or test leads