Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Magnetic Resonance Imaging01:24

Magnetic Resonance Imaging

7.9K
Magnetic resonance imaging (MRI) is a noninvasive medical imaging technique based on a phenomenon of nuclear physics discovered in the 1930s, in which matter exposed to magnetic fields and radio waves was found to emit radio signals. In 1970, a physician and researcher named Raymond Damadian noticed that malignant (cancerous) tissue gave off different signals than normal body tissue. He applied for a patent for the first MRI scanning device in clinical use by the early 1980s. The early MRI...
7.9K
Small-Signal Analysis of MOSFET Amplifiers01:23

Small-Signal Analysis of MOSFET Amplifiers

772
In small-signal analysis, a MOSFET transistor amplifier acts as a linear amplifier when operating in its saturation region. The gate-to-source voltage (VGS) of the MOSFET is the sum of the DC biasing voltage and the small time-varying input signal. This combination sets up the operating point and modulates the drain current (ID) that flows from the drain to the source. When a small AC signal is superimposed on the DC bias voltage at the gate, the instantaneous drain current comprises three...
772
MOSFET Amplifiers01:17

MOSFET Amplifiers

242
The MOSFET, when operating in its active region, functions as a voltage-controlled current source. In this region, the gate-to-source voltage controls the drain current. This principle underlies the operation of the transconductance MOSFET amplifier. The output current is directed through a load resistor to convert this amplifier into a voltage amplifier. The output voltage is then obtained by subtracting the voltage drop across the load resistance from the supply voltage. This process results...
242
Instrumentation Amplifier01:25

Instrumentation Amplifier

750
An electrocardiography (ECG) machine is an essential piece of medical equipment used to monitor the electrical activity of the heart. It operates by detecting small electrical changes on the skin that result from the depolarization of the heart muscle during each heartbeat. However, these signals are in the microvolt range and can be easily overwhelmed by noise or interference.
To overcome this challenge, an ECG machine utilizes an instrumentation amplifier. This specialized amplifier is...
750

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

NMR monitor of <sup>235</sup>U enrichment in UF<sub>6</sub>.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same author

Unmatched delay line NMR probes for magnetic resonance.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same author

Low-field magnetic resonance imaging of roots in intact clayey and silty soils.

Geoderma·2022
Same author

Simple through-plane spatial filter for 2D MRI projections.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2022
Same author

Bioenergy sorghum stem growth regulation: intercalary meristem localization, development, and gene regulatory network analysis.

The Plant journal : for cell and molecular biology·2022
Same author

NMR spectroscopy of coin cell batteries with metal casings.

Science advances·2021
Same journal

Localization-driven exchange contrast in diffusion exchange spectroscopy.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same journal

4.5 Tesla superconducting miniature magnet in liquid nitrogen.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same journal

Folding and unfolding dynamics of a DNA aptamer studied by heteronuclear <sup>1</sup>H-<sup>13</sup>C correlation zz-exchange spectroscopy.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same journal

Multi-spin control from one-spin pulses.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same journal

Altering MRI rotating frame relaxations by changing the truncation level of Hyperbolic Secant pulse.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
Same journal

Effects of proton exchange on the lifetimes of long-lived states in aliphatic chains.

Journal of magnetic resonance (San Diego, Calif. : 1997)·2026
See all related articles

Related Experiment Video

Updated: Oct 8, 2025

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI
11:00

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI

Published on: March 19, 2021

4.7K

Low-cost gradient amplifiers for small MRI systems.

Nathan Evetts1, Mark S Conradi1

  • 1ABQMR, Inc., 2301 Yale Blvd SE, Suite C2, Albuquerque, NM 87106 USA.

Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|December 31, 2021
PubMed
Summary
This summary is machine-generated.

Low-cost audio amplifiers can be modified for use as gradient amplifiers in small Magnetic Resonance Imaging (MRI) systems. This modification provides a cost-effective solution for building essential MRI components.

Keywords:
Current controlGradient amplifierMRINegative feedback

More Related Videos

MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T
10:22

MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T

Published on: January 16, 2021

5.6K
Author Spotlight: Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo
05:26

Author Spotlight: Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo

Published on: May 26, 2023

3.8K

Related Experiment Videos

Last Updated: Oct 8, 2025

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI
11:00

Reliable Acquisition of Electroencephalography Data during Simultaneous Electroencephalography and Functional MRI

Published on: March 19, 2021

4.7K
MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T
10:22

MRM Microcoil Performance Calibration and Usage Demonstrated on Medicago truncatula Roots at 22 T

Published on: January 16, 2021

5.6K
Author Spotlight: Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo
05:26

Author Spotlight: Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain In Vivo

Published on: May 26, 2023

3.8K

Area of Science:

  • Engineering
  • Medical Imaging
  • Physics

Background:

  • Gradient amplifiers are essential components for Magnetic Resonance Imaging (MRI) systems.
  • Existing gradient amplifiers can be expensive, limiting the accessibility of small MRI systems.
  • Audio stereo power amplifiers share similar technical requirements with MRI gradient amplifiers.

Purpose of the Study:

  • To describe the modification of low-cost audio amplifiers for use as gradient amplifiers in small MRI systems.
  • To present a cost-effective solution for building gradient amplifiers for research and educational MRI applications.
  • To demonstrate the feasibility of using modified audio amplifiers for controlled voltage (CV) and controlled current (CC) gradient amplification.

Main Methods:

  • Modification of a Samson Servo 600 audio amplifier to achieve DC coupling for MRI gradient service.
  • Utilizing the inherent characteristics of audio amplifiers, such as their output capabilities (e.g., ±8 A and ±60 V).
  • Incorporating a simple controlled current (CC) front-end circuit for superior performance compared to CV operation.

Main Results:

  • Modified audio amplifiers can function effectively as gradient amplifiers for small MRI systems.
  • The modified Samson Servo 600 demonstrated sufficient output capabilities for MRI applications.
  • A complete 3-axis controlled current gradient system was developed with a total cost of approximately $1200.

Conclusions:

  • Low-cost audio amplifiers represent a viable and economical alternative for gradient amplification in small-scale MRI systems.
  • The described modifications enable the use of readily available audio equipment for specialized MRI applications.
  • This approach significantly reduces the cost barrier for developing and deploying small MRI systems.