EM DC Amplifier

EM DC Amplifier model A22 is a low noise amplifier module for sensitive DC measurements, data collection and systems, and is ideal for very sensitive temperature measurement using thermocouples.
The noise level of the A22 is equivalent to a perfect resistor of about 150 ohms.
When used with normal type thermocouples for temperature measurement, sensitivities of around 20 micro-Kelvin can be achieved. The input voltage drift is very low and is compatible with voltage sensitivities of about 1 nanovolt.
The A22 has many other features desirable in a measurement amplifier. The very high loop voltage gain of 100T, or 280dB, means that high overall gain may be used, controlled precisely by feedback resistors, thus ensuring good linearity, with the accuracy defined by the feedback resistors used.
Despite the high gain, the model A22 is stable with 100% feedback, thus allowing feedback capacitors to be used to filter the output. The input signal level can be up to plus or minus 20 milli-volts and the output can be up to plus and minus 3 volts.
The response time of the A22 is fast, and the gain is reduced to unity at about 20 kHz, thus ensuring good response times, even at high gain settings.
The power supply requirement is low, being about 1.2 milli-amps with power supplies of plus and minus 6 volts, making it ideal for multi-channel measurement systems.
The A22 is designed to be mounted on a printed circuit board, using a 0.1” grid, with 13 pin connections on a rectangle 1.6” X 1.2”, and is built into a heavy gauge mumetal case which gives it very good magnetic, electrostatic and thermal immunity from interference. A printed circuit board is available which provides connections for power supply, gain, filter capacitors and outputs. It also contains controls for voltage and current offsets, power supply de-coupling and a passive output filter to reduce any modulation by-product.