213
Circuit 188:
Active TTL CMOS probe with LED display
Setup information
Install the two transistors, the four diodes and the five resistors as shown in
Fig. 2.188
. The seven jumper
wires come next. Last but not least connect the moving-coil instrument. Check the placement on the board
again and only then connect the battery.
Components required:
2 x 2N3904 transis-
tors, 2 x 1N4148 silicon
diodes, 3 x 1 k
Ω
resis-
tors, 1 x 2.2 k
Ω
resis-
tor, 1 x 10 k
Ω
resistor,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.188:
Active TTL CMOS
probe with moving-coil
instrument
Experiment
The level at the tip of the probe is shown conveniently on the moving-coil instrument. No needle movement
means
low
, full-scale deflection means
high
.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.188.
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...
