Micronta 43-Range Multitester
Micronta Multitester.
Micronta was one of the many brands used by Radio Shack, and sold in the UK by the
Tandy electronics shops. Although the Tandy shops have long gone, one or two of
these meters may still be in use.
To obtain 43 ranges, a "range doubler" switch was included. This had the effect
of halving the FSD voltage or current from that shown on the range selector - and
also doubling the input impedance. For example: with the selector on 50vDC and
the doubler on (V-A/2) the meter would now measure up to 25vDC with an input
impedance of 50,000 Ohms per volt.
General specifications.
*
Ranges: 43.
*
Functions: DC voltage, AC voltage, DC current, resistance, Decibels, continuity test.
*
DC sensitivity: 25K/volt (V-A ranges), 50K/volt (V-A/2 ranges).
*
AC sensitivity: 5K/volt (V-A ranges), 10K/volt (V-A/2 ranges).
*
Meter: 18 microAmp FSD.
*
Batteries: One 1.5v "AA", one 9v PP3.
*
Protection: 750mA 250v fuse.
Specifications.
The specifications below are those stated by the manufacturer, and relate to the
product when new. All test equipment drifts over time and, as with most test
equipment, multimeters should be regularly checked and calibrated to ensure that
they still meet the manufacturers specifications.
Voltage.
|
Range
|
DC accuracy
|
DC accuracy
|
|---|
|
125mV
|
4% of FSD
|
No AC ranges.
|
|
250mV
|
|
1.25v
|
|
2.5v
|
|
5V
|
3% of FSD
|
4% of FSD
|
|
10V
|
|
25V
|
|
50V
|
|
125V
|
|
250v
|
|
500v
|
4% of FSD
|
|
1000v
|
DC current.
|
Range
|
Accuracy
|
|---|
|
25 microAmp
|
3% of FSD
|
|
50 microAmp
|
|
2.5 milliAmp
|
|
5 milliAmp
|
|
25 milliAmp
|
|
50 milliAmp
|
|
250 milliAmp
|
|
500 milliAmp
|
|
5 Amp
|
|
10 Amp
|
Resistance.
|
Range
|
Accuracy
|
|---|
|
2000 Ohms
|
3% of full scale
|
|
20K Ohms
|
|
2M Ohms
|
|
20M Ohms
|
Continuity test.
|
Readout
|
Meter and sound
|
|
Sound
|
Buzzer
|
|
Continuity resistance
|
Below 300 Ohms
|
Schematic diagram.
The diagram for this equipment can be found in the
diagram database.
