BRUEL & KJAER 2719 User Manual

Power Amplifier Type 2719 – User Manual12
Power Output
Fig.4.1 Output impedance of Type 2719 as a function of frequency and V/C Mode switch setting
The power output of Type 2719 is direct-coupled. Its output impedance, shown in Fig.4.1,
depends on the feedback setting selected using the V/C Mode switch.
In Voltage Mode (low impedance), a fraction of the voltage developed across the moving coil
of the exciter is used as feedback. This gives the amplifier constant voltage characteristics –
very low output impedance and constant output voltage with frequency – producing the best
acceleration waveform. It is, therefore, suited to most single-exciter applications as well as to
multiple-exciter applications at low frequencies where it is important that the exciters have the
same motion.
In Current Mode (high impedance), feedback is proportional to the current flowing in the
exciter’s moving coil. This gives the amplifier constant current characteristics – high output
impedance and constant output current with frequency – necessary to obtain a constant force
with the exciter regardless of changes in the test object. This is useful for single-exciter fatigue
tests and multiple-exciter resonant mode studies of vibration test objects.
Low Impedance Specification Limit
High Impedance Specification Limit
1k
500
200
100
50
20
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
0.005
0.002
0.001
O
utput Impe
d
ance
(Oh
m
)
1
2
5
10
20
50
100
200 500
1k
2k
5k
10k
20k 50k 100
k
Frequency (Hz)
010101

BRUEL & KJAER 2719 Specifications

General

Brand	BRUEL & KJAER
Model	2719
Category	Amplifier
Language	English