Sequoia AMP4100

4 Channel voltage amplifier

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Key Features

The AMP4100 is a 4 channel amplifier designed for use with 2x HFM-8 E-H or HFM-8 E-L heat flux sensors.

The HFM-8 E-H and HFM-8 E-L heat flux sensors have an embedded thermocouples. These don't work in the same manner normal thermocouples but do produce low level voltages that can require amplification. The AMP4100 takes the heat flux and thermocouple outputs from 2 sensors and amplifies these to meet the requirements of the attached data logging equipment.

The AMP4100 uses high quality Lemo connectors to match those provided on the heat flux sensors. 2 spare connectors are provided with the product so that the external data logger equipment can be wired into the output. We use Lemo part number EPG.0B.304.HLN for our inputs if you need to source any more connectors for any reason (specify a male connector to mate with this).

Gain on the 2 thermocouple inputs and 2 heat flux inputs is fixed at the factory and can be specified at between 10 and 10,000. Non-standard gains can be set if required to meet special requirements. Because heat flux can flow into and out of the sensor, the heat flux sensor output can go positive and negative. The amplifier is supplied with a low noise ±15V linear power supply to allow amplification of positive and negative inputs. In addition, it is possible to specify inputs with a low pass filter of 100mS time constant if required by the application. Zero is set at the factory and offsets can be applied at this time by special order.


Amplifier Specification

Power Supply ±12 to ±15V
Supply Current 32mA
Output: ±10V
Maximum Load 5KΩ
Rise Time 2mS 10-90%, G=1000
Zero Temperature Coefficient 0.1µV/°C
Input noise voltage 0.2µV peak-peak 1-10Hz
Span Temperature Coefficient 30ppm/°C typical
Gain Tolerance ±0.1% (0.25% at G=10000)
Input Bias Current 1nA

Whats in the box?

  • AMP4100 amplifier
  • ±15V linear power supply (switchable 115V / 230V, 50-60Hz operation) with UK and European power cords
  • 2 male Lemo connectors

Ordering Options

Part numbers are constructed as follows:


AMP4100 = Model number
HFGain1 = Gain of Heat Flux Channel 1
TGain1 = Gain of Temperature Channel 1
HFGain2 = Gain of Heat Flux Channel 2
TGain2 = Gain of Temperature Channel 2

Add "F" to the end of the gain to specify the 100mS filter

Example: AMP4100-1000-25F-1000-25F specifies an amplifier with Heat Flux input gains set to 1000 and Temperature input gains set to 25 with the 100mS filter applied.