In scans in the tunnel microscope to actuate the operating equipment the piezoelectricity tubular locator to need to use pulls down the electric current driving circuit high. Shown in Figure 1 the electric circuit to have 6 kHz - the 3dB band width, may actuate the high-resistance low electric capacity’s piezoelectricity load. This electric circuit cost is low, may replace the commercial driver. Transistor Q3 and Q4 constituted an electric current reflector, R3 have established Q4 the collecting electrode electric current. This collecting electrode electric current may determine by the IC3=IC4=[VCC-(-VCC)-VBE(Q4)]/R3 formula. Operational amplifier IC1 is Q5 provides the base electrode actuation, Q5 actuates Q6. When the IC1 input end does not have the signal, Q6 and Q3 collecting electrode current balance, but is from emitter follower Q1 and the Q2 junction loses the origin is 0V.
The input signal will add to IC1, may urge IC1 the output to achieve 12V or negative 12V supply voltage. Causes IC1 to output saturated, possibly has the enough slewing rate to retard has the vibration. Although uses high speed operational amplifier LF411 to be possible to improve this amplifier’s band width and the slewing rate, but counter parallel diode D1 and D2 limit the IC1 output displacement in a diode forward voltage drop, thus improved the stability.
You may through adjust R7 maximum limit to reduce the direct-current output offset voltage and the slewing rate. According to the experience, the R7 resistance number should take the R9 resistance number two times. R9 and the R8 ratio of resistance number establishes amplifier’s gain. Figure 2 showed R7 and R9 took when the best resistance number the input and the output wave shape. What must pay attention, Q1 and the Q2 VCEO rated value and - VCC limits VCC in 300V.
