107
Circuit 82:
Handy diode tester with moving-coil instrument
Setup information
Install the transistor and the two resistors as shown in
Fig. 2.82 followed by
the three jumper wires. Last
but not least connect the moving-coil instrument. Check the placement on the board again and only then
connect the battery.
Components required:
1 x 2N3904 transistor,
1 x 4.7 k
Ω
resistor,
1 x 22 k
Ω
resistor,
1 x moving-coil instrument,
1 x breadboard, 1 x 9V bat-
tery with clip connector
Fig. 2.82:
Handy diode tester
with moving-coil instrument
Experiment
If everything is wired correctly, you can safely go ahead and test any kind of diode. The measuring current is
so low that the most fragile diodes won’t blow. If the test diode is connected in forward-biased, the needle
of the moving-coil instrument shows a clear deflection. If connected the other way round (reverse-biased),
there is no deflection – that would be the result for a good diode. The diode is bad, if in both cases the
result shows a needle deflection on the meter or if in both cases the needle remains at zero.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.82.
Summary of Contents for ELECTRONICS EXPERIMENTS BOX
Page 4: ......
Page 265: ...267 Fig 3 56 Cir cuit 56 Audio limiter Fig 3 57 Circuit 57 Amplifier for a storm detector...
Page 269: ...271 Fig 3 64 Circuit 64 Stabilizer for 1 9 V Fig 3 65 Circuit 65 Stabilizer for 2 5 V...
Page 275: ...277 Fig 3 80 Circuit 80 Quiztimer 30 seconds Fig 3 81 Circuit 81 Handy diode tester...
Page 315: ...317 Fig 3 179 Circuit 179 HF generator 150 kHz Fig 3 180 Circuit 180 HF generator 420 kHz...
