TD250 V8 Manual
15
Rev 2, 31-09-2020
This configuration is also referred to as the “Full Length” configuration [1]. The performance of this
method is compared to other configurations in reference [1].
In the driven internal electrode configuration, the X and Y electrodes are driven in the standard way
with equal and opposite voltages, as shown in Figure 11. By applying a negative voltage to the
internal electrode, a contraction equal to half the vertical scan range can be obtained. That is, the
vertical deflection is
Δ𝐿 = 𝑉
𝑧
𝑑
31
𝐿
ℎ
where
𝑉
𝑧
is a strictly negative voltage applied to the internal electrode.
This method exploits the higher positive electric field strength of the piezoelectric material, which is
usually five times the negative electric field strength. Care must be taken not to apply positive
voltages to the internal electrode since this can lead to depolarisation. For example, when using a
non-inverting channel, the input is enforced to be negative as shown in Figure 11. Alternatively, an
inverting channel can be used and the input is enforced to be positive.
Figure 11. Driving piezoelectric tubes with the TD250-INV (driven internal electrode configuration)
Piezoelectric tubes with prewired connections are available from
. Prewired tubes can also
be supplied with D-sub connectors for direct connection to the TD250 output cable.
References
[1] Electrode Configurations for Piezoelectric Tube Actuators with Improved Scan Range and Reduced
Cross-Coupling; D. S. Raghunvanshi, S. I. Moore, A. J. Fleming, and Y. K. Yong; IEEE/ASME Transactions
on Mechatronics, 2020,
