E X P E R I M E N T A L PR O B L E M
Problem
Inside a black box provided with three terminals labeled A, B and C, there are three electric components
of different nature. The components could be any of the following types: batteries, resistors larger then
100 ohm, capacitors larger than 1 microfarad and semiconductor diodes.
a)Determine what types of components are inside the black box and its relative position to terminal A, B
and C. Draw the exploring circuits used in the determination, including those used to discard circuits
with similar behaviour
b)If a battery was present, determine its electromotive force. Draw the experimental circuit used.
c)If a resistor was present, determine its value. Draw the experimental circuit used.
d)If a capacitor was present, determine its value. Draw the experimental circuit used.
e)If a diode was present, determine V and V, where V the forward bias threshold voltage and V is the
o r o r
reverse bias breakdown voltage.
f)Estimate, for each measured value, the error limits.
The following equipments and devices are available for your use:
1 back box with three terminals labeled A, B and C;
1 variable DC power supply;
2 Polytest 1 W multimeters;
10 connection cables;
2 patching boards;
1 100 k, 5 % value resistor;
1 10 k, 5 % value resistor;
1 1 k, 5 % value resistor;
1 100 F, 20 % value capacitor;
1 chronometer;
2 paper sheets;
1 square ruler;
1 interruptor.
Voltmeter internal resistance.
Scale Value in k
0-1 V 3,2 1 %
0-3 V 10 1 %
0-10 V 32 1 %
0-20 V 64 1 %
0-60 V 200 1 %
Ammeter internal resistance.
Scale Value in
0-0,3 mA 1 000 1 %
0-1 mA 263 1 %
0-3 mA 94 1 %
0-20 mA 30,4 1 %
0-30 mA 9,84 1 %
0-100 mA 3,09 1 %
0-300 mA 0,99 1 %
0-1 mA 0,31 1 %
Notice: Do not use the Polystes 1 W as an ohmmeter. Protect your circuit against large currents, and do
not use currents larger than 20 mA.
Give your results by means of tables or plots.
When drawing the circuits, use the following symbols: