Hinweis: der BA4850 wird nicht mehr produziert

BA4825/BA4850 – High Speed Bipolar Amplifier

BA Series are power amplifiers that handle DC to 50 MHz (max.) signals and output broadband, high speed, and high voltage (300 Vp-p max) bipolar (both positive and negative polarities) outputs. While ordinary DC power supplies only supply one-way currents, the BA Series amplifiers supply (source) and absorb (sink) currents, and handle positive and negative voltages as well, because they operate across all four quadrants.

Product Information




BA4850 – Discontinued

BA4825BA4850 – Discontinued
BroadbandDC to 2MHzDC to 50MHz
High-power output voltage100Vrms (300Vp-p, 0.5Arms±20V, ±1A
High slew rate500V/µs6000V/µs
Low output impedance0.5Ω+1.5µH or less (typ.)3.3Ω+0.01µH or less (typ.)
Bipolar outputFour-quadrant operation that enables positive and negative voltage and current to be supplied (source) and absorbed (sink).
Multiple functionsOuput polarity switching, output range shift, ouput monitoring, external output on/off control, DC bias addition and DC offset adjustmentOuput polarity switching external ouput on/off control and DC offset adjustment


Available for capacitive and inductive loads

If a load containing a capacitor or coil is driven with alternating current, the current generally flows back from the load. In this case, an ordinary power supply or amplifier may not be able to drive the load. BA series amplifier also operates (i.e., outputs the current) with a capacitive or inductive load such as a piezoelectric element or solenoid. This is because it operates also with a sink, where the voltage and current directions are reverse.


Broadband, high speed, and high-voltage

BA4850 faithfully reproduces pulse signals with quick rise and complex waveform signals as well, because the frequency band is DC to 50 MHz and the slew rate is 6,000 V/µ s.
BA4825 drives current from a large piezoelectric element or display device, because the band is DC to 2 MHz and the maximum high-voltage output is 300 Vp-p.
Because both can amplify DC, they can be input waveforms containing an offset or those that are asymmetric in the positive area and negative area.


Low output impedance

BA series keep a low output impedance throughout the overall range (0.5Ω + 1.5 MHz or less typ. for BA4825). With the voltage drop (raised due to load connection) suppressed to the minimum, the power of the equipment is maximized.


Multiple functions

  • Range shifting function*1 for changing output range.*1
  • DC bias addition function*1 for adding direct current (bias) to the output.
  • DC offset adjustment function for setting DC offset in output to 0 (zero).
  • Equipped with output voltage monitor terminal (BNC, monitor ratio 1/100)*1 and monitor meter (output voltage/current switching display)*1.
  • Output on/off can be switched from the panel or externally controlled.
  • Output polarity switching (INVT) for setting the device to either an in-phase or reversed-phase amplifier. Use of reversed-phase output enables BTL*2 connection, which doubles the output voltage and power, using two BA Series amplifiers.
  • Two systems, A and B, for input. Switching and addition of the input by pressing a single key*1.
  • Input impedance switcheable between 50Ω and 10kΩ*1
  • The settings at power-on can be set using the dip switches on the rear panel.
  • The power input is available for worldwide applications (AC100 to 230 V).


*1 : BA4825 function *2 : Balanced Transformerless



Driving and evaluation of piezoelectric elements

High voltage and high speed are required when a piezoelectric element used for a piezoelectric inverter or piezoelectric actuator is to be driven and evaluated.
In addition to high-voltage output, BA Series amplifiers keep extremely small output impedance. Therefore, they can offer superior step response against piezoelectric with large capacitance piezoelectric element.

Test and evaluation of display devices

Flat display panels such as FEDs and LCDs require high voltage for driving, and quick rise for evaluation of their response characteristics.
With their high-voltage output and high slew rate, BA series amplifiers enable accurate drive tests and evaluations.

Power amplifier for signal or pulse generators

During evaluation process of power devices, the performance is evaluated with a broadband, high voltage, and large current.
With their broadband, high speed, and high voltage output, BA series amplifiers evaluate and test devices, using various waveforms, pulse patterns, and arbitrary waveforms.

Measurement of magnetizing characteristics (B-H curves)

BA series can be used for magnetization measurement such as ferrite and or amorphous materials.
Since the BA Series features the high frequency of 50 MHz required for measuring B-H curves, as well as high voltage output and high stability against inductive loads, you can reproduce stable measurement.


  • Driving of elastic surface wave ultrasonic motors and comb tooth-shaped electrodes in the field of nanotechnology and MEMS

  • High-frequency ripple tests of capacitors

  • Development of ink jet application technology

  • Characteristics tests for semiconductors such as diodes and SCRs

  • Characteristic test for the devices such as relays and switches

  • Research and development of IC cards

  • Driving use of devices and materials and other R&D use in the leading edge technology field




BA4825 BA4850 – Discontinued
Frequency band DC to 2MHz DC to 50MHz




BA4825 BA4850 – Discontinued

Maximum output voltage

±150V range (rated resistance load 200Ω)

±20V (rated resistance load 50Ω)
DC to 20MHz
±14.2V (rated resistance load 50Ω)
20MHz to 50MHz

100Vrm or greater 40Hz to 500kHz
70Vrms or greater 500kHz to 1MHz
40Vrms or greater 1MHz to 2MHz
±150V range (rated resistance load 450Ω)
±150V (300Vp-p) DC to 500kHz
±100V (200Vp-p) 500kHz to 1 MHz
±56V (112Vp-p) 1MHz to 2MHz
+250V range (rated resistance load 1,250Ω)
-50V to +250V DC to 500kHz
+40V to +240V 500kHz to 1MHz
+80V to +200V 1MHz to 2MHz
-250V range (rated resistance load 1,250Ω)
-250V to +50V DC to 500kHz
-240V to -40V 500kHz to 1MHz
-200V to -80V 1MHz to 2MHz
Rated output current 0.5Arms
(±150V range, rated resistance load 200Ω)
±1A, DC
Output power Constant voltage (CV)
Output polarity In-phase or reversed (toggled with the panel switch)
Characteristics of small amplitude frequency DC to 100kHz, ±0.5dB
100kHz to 2MHz, +1, -3dB
Output amplitude 20 Vrms, reference 1kHz
DC to 100kHz, ±0.5dB
10kHz to 5MHz, +1, -3dB
Ouput amplitude ±4V, reference 1kHz
Gain setting Fixed: x1, x10, x20, x50
Variable: x1 (CAL) to x3, consecutive
The set gain equals to (Fixed + Variable)
Fixed: x1, x2, x5, x10
Variable: x1 (CAL) to x3 consecutive
The set gain equals to (Fixed + Variable)
Slew rate 500V/µs 6000V/µs
Ouput DC offset Adjustment range: ±0.5V or more (input terminal short circuit)
Output DC bias ±200V or more
Allows tunning on/off by the front panel switch.
Output impedance 0.5Ω + 1.5µH or less (typ.) 3.3Ω + 0.01µH or less (typ.)
Output terminal BNC connector (front panel), Lo side grounded to the cabinet
Monitor output 1/100 of output voltage, in-phase -
Monitor meter Displays output voltage or current
(toggled with the switch)
Output on/off Front panel switch or external control input



BA4825 BA4850
Maximum input voltage


Number of terminals 2 (A input: Front panel, B input: rear panel)
(Input type may be A input, B input or both A input and B input)
1 (Front Panel)
Input terminals BNC connector, Lo side grounded to the cabinet
Input impedancer 5Ω and 10kΩ, switchable 50Ω



BA4825 BA4850
Protection function Output overcurrent, output overvoltage, power section failure, abnormal internal temperature
External control input/output 2 (A input: Front panel, B input: Rear panel)
(Input type may be A input, B input or both A input and B input)
Settings at power-on Settings power-on made by dip switches on the rear panel
(10 settings for BA4825 or 4 settings for BA4850)
Power input AC100V to 230V ±10% (at 250V or less), 50Hz/60Hz ±2Hz
Power consumption 350VA or less 200VA or less
Operating temperature and humidity 0 to +40°C, 5 to 85%RH
(Absolute humidity 1 to 25g/m³, no condensation)
Dimensions (mm) 258(W) x 132.5(H) x 390(D) (not including protrusions)
Weight Approx. 7kg


BA4825 output voltage and current range

For AC

AC Output

For DC

DC Output