probe. The two lead wires are shown attached to correctly measure the current of a
Make all connections with voltage not applied.
After checking all
connections, turn the circuit on and read the meter.
MX-1410U, the high-voltage test probe (fig 1-18), extends the DC voltage
range to 5000 volts. Notice that the function switch is in the 20K position, the
range switch must be set at 500, and the high voltage test probe is connected to
the positive test lead.
The MX-1441U test adapter (fig 1-18) is used to make crystal current
measurements requiring a 1000-ohm load as seen from the plug end of the adapter.
The CX-2140U test Lead set (fig 1-18) includes a pair of four-foot test
These test leads have interlocking plugs installed at their set ends and
test probe tips at the other end. Detachable alligator clips are also provided to
fit over the test probe, to hold a component or clip on to a part of the circuit.
Learning Event 5:
DETERMINE THE VALUE OF R IN FUNCTION AND RANGE SETTINGS
The PSM-6 has a range switch allowing you to select DC voltage ranges of 0.5,
2.5, 10, 50, 250, 500, and 1000 volts. Further, since DC voltage may be checked at
a sensitivity of either 1000 ohms/volts or 20,000 ohms/volts as selected by the
function switch on the panel of the instrument operation (primarily the same
regardless of whether the 20,000-ohms/volt or the 1000-ohms/volt function is
selected), we will only discuss the 1000 ohms/volt operation. Figures 1-19 and 1-
20 illustrate and identify both simplified circuits; if you know the operation of
one, you can easily understand the other.
With the function switch set at the DCV Kohm/V position and the range switch
at any position, the simplified circuit in Figure 1-19 shows the basic circuit
configuration used to check DC voltages.
Note in the diagram the range settings
are obtained by the selection of resistors of various sizes. For example, when the
range switch is in the 50 position, the value of R is such that 50 volts applied
across the meter provides full-scale deflection. If the range switch is changed to
position 10, then the value of R is such that 10 volts applied across the meter
causes full-scale deflection, etc.