210
Circuit 185:
Peak level display with LED
Setup information
Install the transistor, the diode and the four resistors as shown in
Fig. 2.185
followed by the jumper wire.
Check the placement on the board again and only then connect the battery. If you are familiar with the
relevant safety guidelines as per VDE and know how to observe them when working with devices that are to
be connected to the mains, you can now connect the audio amplifier.
Components required:
1 x 2N3904 transistor,
1 x BAT85 Schottky
diode, 1 x 220
Ω
resis-
tor, 1 x 1 k
Ω
resistor,
1 x 10 k
Ω
resistor,
1 x moving-coil instru-
ment, 1 x breadboard,
1 x 9V battery with clip
connector
Fig. 2.185:
Peak level display
with moving-coil instrument
Experiment
The circuit responds to low-frequency signals. The moving-coil instrument shows deflection at an NF input
voltage of 0.3V and full-scale deflection at an NF input voltage of 1.5V. You can test the circuit on the speaker
output of an audio amplifier or perfectly safe on the speaker jack of a portable radio.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.185.
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...
