Amplifiers

A low-noise amplifier like the DAM50 is an excellent choice for EEG recording in rodents. WPI's amplifiers were engineered for the bio-medical researcher. While 20-30μV of noise is common in bio-amplifiers, WPI’s DAM series amplifiers generate 0.4μV RMS (root mean squared) at 0.1-100Hz. (That’s equal to about 2μV peak to peak.) This setup shows one way such recordings could be made. The RC1 electrode works well for rats, and the EP1 is more suitable for mouse cranial application.

For this application, you will need the following equipment:

• (1) DAM50 amplifier
• (1) MD4R micromanipulator...more

An amplifier, in simplest terms, is an electronic device that magnifies an input signal. However, the way an amplifier is designed to handle noise and bandwidth limitations greatly affects the quality and sustainability of the final output signal.

Defining Terms

To knowledgeably discuss amplifiers, let’s define a few terms.

• Gain – The gain is the multiplier defining how much the amplitude of an input signal is increased. A signal with an X1 gain is not amplified. An X10 gain produces an output signal ten times greater than the input signal.
• Noise – Any unwanted signal fluctuations are called noise. While noise can also result from external sources, for the purpose of this discussion, we are primarily concerned with the noise resulting from the inner workings of the electronic device, our amplifier. This intrinsic noise is called shot (or schott) noise.
• Signal to Noise Ratio (SNR) – The ratio of the output signal...more

Dri-Ref™ reference electrodes were developed by WPI to have extremely low electrolyte leakage properties, hence the name “Dri-Ref.” In addition to this key feature, these electrodes exhibit stable and reproducible potential and low resistance. Stored in KCl when not in use, they have a long life expectancy. Low leakage is achieved by using KONBO™, a product combining modern ceramic and conductive polymer technology, as the liquid junction. Electrode resistance is low, an important consideration when making low-noise measurements.

Although the internal filling solution contains KCI, the low fluid leakage means Dri-Ref may be used in combination with ion selective electrodes, including those for K⁺ and Cl^-, without significant contamination from the reference electrode.

The Dri-Ref electrodes are chemically resistant to strong acids and alkalines. Dri-Ref electrodes are not suitable for use in organic solvents. In addition, the long, thin ...more