Catalogs >
Bruel and Kjaer >
Power Amplifier Type 2718

Power Amplifier Type 2718
2Pages

Catalog excerpts

BRÜEL & KJÆR ® Power Amplifiers Power Amplifier Type 2718 Power Amplifier Type 2718 has been designed to drive small vibration exciters, particularly Vibration Exciter Type 4809, which has a force rating of 45 N (10 lbf) sine peak, and Mini-shaker Type 4810, which has a force rating of 10 N (2.25 lbf) sine peak. Type 2718 provides a flat frequency response and low harmonic distortion over a wide frequency range and has extensive control and monitoring capabilities. Uses • Drives Vibration Exciter Type 4809 • Drives Mini-shaker Type 4810 safely to full rating • General purpose power amplifier for small vibration exciters requiring up to 75 VA in 3 Ω Features • 75 VA power output capacity in 3 Ω • Continuously variable current limit from 1 A to 5 A (RMS) • 40 dB voltage gain Description Power Amplifier Type 2718 has a flat frequency response from 10 Hz to 20 kHz (±0.5 dB). The power output capacity is 75 VA into a 3 Ω exciter or resistive load, and the maximum voltage gain is 40 dB. This enables the power amplifier to be used in acoustical measurement setups, even when third-octave, narrow-band noise is employed. The use of a transformerless power output stage and high negative feedback results in very low harmonic distortion. A balanced preamplifier and rugged solid-state design results in a stable instrument which can tolerate temperature fluctuations and supply line variations. Fig. 1 Simplified block diagram of Power Amplifier Type 2718 Cont. Variable Current Limit 1 A to 5 A (RMS) Input AƩenuator Gain Control Power Ampliﬁer Monitoring The front panel has extensive monitoring capabilities including an LCD that shows output current and output voltage and LEDs that light up when the instrument is in the following states: distortion, temperature overload, current overload, stand-by status and power on. The output current and voltage can also be monitored using two BNC connectors on the back panel. • Built-in attenuator and continuously variable gain control • Low distortion over wide frequency range • Built-in protection against short-circuit and excessive heat sink temperature • LEDs on front panel showing distortion (clipped output signal), temperature overload, current overload, output signal phase (0° or 180°) and power status • Liquid crystal display (LCD) showing output current and voltage • Monitor output connectors (voltage and current) on back panel Clipping Detection The input circuitry of Type 2718 includes a continuously variable attenuator for attenuation of the input signal. This is followed by a gain control, in 10 dB steps from 0 to 40 dB, and a preamplifier. The preamplifier is capacitively-coupled to the driver stage, which is equipped with a clipping detector. Excessive signal levels at the input will saturate the amplifier and cause clipping of the output waveform. This will trigger the clipping detector, which then lights the yellow distortion warning LED on the front panel. The instrument remains in operation during clipping. Temperature Protection The power stage employs an output current limiter, which limits the instantaneous positive and negative peaks of the output current. The power output stage is protected by a temperature sensing device. Abnormal load conditions, high ambient temperatures or an output short-circuit could result in output transistor temperatures well in excess of design limits. To prevent any subsequent damage, the temperature protective circuitry blocks the amplifier input signal. When the heat-sink temperature reverts to the normal level, the power amplifier will automatically regain operation. Phase Shift The output signal can be phase inverted (0° or 180°) by use of the phase inversion switch at the front panel. Two LEDs – one for each of the two possible positions – indicates the cho

Open the catalog to page 1

Specifications – Power Amplifier Type 2718 China RoHS mark indicates compliance with administrative measures on the control of pollution caused by electronic information products according to the Ministry of Information Industries of the People’s Republic of China WEEE mark indicates compliance with the EU WEEE Directive Safety, EMC Emission and Immunity: According to relevant standards: • EN/IEC 61010 –1, UL 61010–1 • EN/IEC 61000–6–2 • EN/IEC 61000–6–4 • CISPR32 Class A limit • FCC Rules Part 15 Temperature: According to IEC 60068–2–1 and IEC 60068–2–2 • Operating temperature: +5 to +40...

Open the catalog to page 2

Power Amplifier Type 2718 2Pages

Catalog excerpts

All Bruel and Kjaer catalogs and technical brochures

Power Amplifier Type 2718
2Pages