Brownlee Amplifiers

• General Purpose Instrumentation Amplifier – Model 410
Brownlee’s rugged yet easy-to-use amplifiers have four channels of a high gain/low noise amplification, lowpass filter and output offset control. A control knob adjusts amplifier parameters, and an alphanumeric LED readout displays values. There is a memory function for each channel. Input voltage noise is only 1.5µV rms.

• Amplification with sophisticated filter circuitry – Model 440
In addition to the Model 410’s features, the Model 440 offers an 8-pole Bessel lowpass filter, Auto-Zeroing, a line-notch filter, highpass filter, multiple memories per channel, and a digital voltmeter on 2 channels. A wide bandwidth of over 500 kHz at all gains insures smooth recordings.

Brownlee Precision Model 410

The Brownlee Precision Model 410 is a four-channel general purpose laboratory amplifier (one channel shown at right). It can be used to amplify small signals from sources which may have a large common-mode level and high frequency noise. Each channel consists of a high gain/low noise amplifier, an input coupling selector, a 2-pole lowpass filter, and an output offset control. A control knob sets the amplifier parameters and the values are displayed on a bright LED alphanumeric readout.

• Clear front panel controls for all settings
• Calibrated gains from 0.1 to 10,000
• Single-ended or differential inputs
• 2-pole elliptic lowpass filter with range 1 kHz to 25 kHz
• AC or DC input coupling
• Output offset control to shift output up to +/- 10 Volts
• Low noise circuitry
• Self-trimming feature to remove internal offsets
• Memory on each channel
• Powerful output which can directly drive transducers
• Wide bandwidth: greater than 200 kHz on all gains

Brownlee Precision Model 440

The Brownlee Precision Model 440 incorporates four channels of sophisticated amplifier and filter circuitry in a friendly easy-to-use instrument. Each channel consists of a high gain/low noise amplifier, an 8-pole Bessel lowpass filter, a highpass filter, a line notch filter, and output offset controls. A control knob sets the amplifier parameters and the values are displayed on a bright LED alphanumeric readout.

• Clear front panel controls for all settings
• Gains from 0.1 to 10,000 in fine, calibrated steps
• Single-ended or differential inputs
• 8 pole Bessel lowpass filter with range 20 Hz to 50 kHz
• Highpass filter with frequency range .01 Hz to 100 Hz
• Output offset control to shift output up to +/- 10 Volts
• Auto-Zero feature to reset the output to the baseline level
• Notch filter to suppress line noise
• Digital Voltmeter on channels 1 and 2
• Memories which hold multiple setups
• Powerful output which can directly drive transducers
• Wide bandwidth: greater than 500 kHz on all gains

Brownlee Precision Model 410

Close-up view of one Brownlee Precision Model 410 channel. Notice the multi-use display and individual channel memory. The selector knob uses an optical encoder instead of potentiometer for extremely quiet operation.

Brownlee Precision Model 440

The Model 440 adds controls for a highpass filter, notch filter, digital volt meter, auto zero, and input impedance on each channel.