Furuno FCV-1200L Service Manual page 43

Procedure 2 : using the impedance check circuit with sweep generator.
Vs(Vpp)
Figure 7.3 Resonant characteristic check circuit using sweep generator
Figure 7.4 shows the resonant characteristic of the transducer "50B-6B", measured by the check
circuit shown in figure 7.3.
Impedance
Figure 7.4 Resonant characteristic of transducer type 50B-6B
Since the waveform differs with the resister "R" and the measuring condition, i.e., in water or in air,
the resister and measuring condition must be the same when checking the transducer.
Note: when check a transducer in water, sufficient clearance below transducer is required.
Figure 7.4 on the next page shows the sample waveforms of the normal and defective transducer
"type 50B-12" measured in water (depth is 2 m, more or less)
The waveforms ringed in figure 7.4 show a defect of the transducer.
R
POT
S.G.
Sweep
Oscilloscope
Generator
50B-6B (Sweep Range: 10 to 80 kHz)
40
Transducer
Frequency
Fo (50kHz):Center of Scale