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What is the difference between a power supply and a amplifier ?


Bandwidth or small signal bandwidth and slew rate , are both often misinterpreted terms when speaking of amplifiers . These terms and their effects on the functionality of an amplifier need to be understood first. Please read our  White Paper WP- 8: bandwidth and slew rate


What is the difference between a power supply and a amplifier ?

A power supply has as a reference or voltage control an unipolar DC voltage. Accordingly, the output voltage is a DC voltage. A power supply can usually only deliver power ( function of a source) and not absorb it (function of a sink). In an amplifier , the control voltage (input voltage) may have any uni- or bi-polar waveform. Sinus-, square- or pulse -shaped signals , superimposed with a DC voltage component , are common. The waveform of the output voltage (or output current ) corresponds to the input signal. The HUBERT power amplifier can be operated as source and sink . ( See also White Paper WP- 1: HUBERT 4- quadrant amplifiers)


Why are the A1110 series amplifiers equipped with a symmetrical input?

A symmetrical (balanced) input is part of a symmetrical signal path. The contexts and advantages are discussed in our White Paper No. 4.

Why does the amplifier switch to Protection when I change the output level at my function generator although the permissible operating values have not been exceeded?

In many industrial function generators change of the output level is realized through switch-over of a relay matrix. The switching pulses occurring during this process generate transients in the amplifier which cause temporary increase of the output current. If the amplifier is already operated “near” its maximum operating values, this results in activation of the current shut-off or dissipation power shut-off. In addition to trouble-free change of the input level, the following procedure could be a feasible solution: Switch on the operable amplifier with the load connected (amplifier on, the output relay is switched on); Mute the amplifier (amplifier off, only the amplifier input is switched off); Set the generator to the required level; Switch the amplifier on (amplifier on).

I connected a 0.5 Ohm load to my A1110-16-E. Why does the amplifier shut off at 12 A DC current already, although 28 A are specified?

Possible cause: The selected operating voltage is not correct. With an output current of 12 A at the 0.5 Ohm load an output voltage of 6 Volt and power of 66 W is generated. Certainly not too high. However, with high operating voltage (Ub=90 V) dissipation power of Pv=(90-6) V * 12 A = 1128 W is generated in the amplifier, which is not permissible (see also U-I diagrams in the data sheets) and causes shut-down. Low operating voltage is a better choice here.

For my application I need a temporary higher load current than specified in the data sheet. Is this possible?

Yes, with devices of the A1110-x-xE amplifier range this is possible within certain limits. Please specify your concrete requirements.

I connected a ferrite choke and suddenly the amplifier shuts off at level sweep although the permissible operating values have not been exceeded. Why?

One possible cause may be that the ferrite reaches saturation. Inductivity is dropped and thus impedance shifts to the small, resistive part of the choke. As a consequence, increased output power occurs, which exceeds the permissible maximum and triggers the protective circuit.