Questions tagged [medical]

For applications in the medical arena that will come in contact with a patient. In general these applications need to satisfy international standards such as IEC60601. These applications have stringent patient isolation constraints, capacitive leakage constraints, mode of failure constraints, and voltage or current limits that can impose considerable design limitations.

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What is the reference voltage of Vin- and Vin+ in this circuit?

I'm trying to make a PCB board to measure Electrocardiogram (ECG) signal. I have some doubts about the DC offset of the 2 input signals (\$V_{IN-}\$, \$V_{IN+}\$) with reference to analog ground. I ...
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90 views

How to convert the outputs from the MAX30003 and/or AD8232 ECG modules to millivolts (mV)

I have been working with the MAX30003 and AD8232 ECG modules for a while now and I am trying to figure out what the raw outputs from both modules correlate to. I cannot seem to find any information ...
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3 votes
3 answers
343 views

Difference between a normal tactile switch/pushbutton and a detection switch/pushbutton

What is the general difference between a normal tactile switch/push button and a detection switch/push button? I have heard that if in an application, for example, a pushbutton has to be pressed for a ...
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2 votes
1 answer
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AC filtering: Medical vs Standard Version

I am looking at that Schurter's AC power entry modules to choose a AC filtering module and at page 5 I noticed the differences between Standard version and Medical version: Their only difference is ...
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1 answer
81 views

Risk of getting shocked by ECG leads? [closed]

I have recently come into possession of a GE patient monitor (Eagle 4000) which looks structurally sound, probably decommissioned because of its age. It seems to work without a hiccup but I remembered ...
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38 views

Is there a standard equivalent to automotive standard AEC-Q200 for the medical sector?

I want to ensure components of high integrity characteristics are utilised in a design by a third party. In the automotive sector AEC-Q200 can be stipulated, e.g. (https://www.digikey.com/en/product-...
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What is a good SNR for a medical device like a pulse oximeter?

What is a good SNR for a medical device like a pulse oximeter? Is there a U.S. Federal standard for this? Thanks!
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1 vote
1 answer
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Voltage / amperage / setup for tingling sensation

There are small pens (powered by a single or double 1.5V battery) or other medical devices that upon touching your skin produce a tingling sensation. Main question: I wonder to what voltage, amperage ...
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8 votes
2 answers
575 views

Medical electronic devices quality

Is there a special grade for electronic components made to be used in medical devices such as life support systems? I have read in most data sheets that "this product is not to be used in life support ...
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0 votes
2 answers
146 views

Pressure sensor without using MEMS chips [closed]

I'd like to figure out how to make a pressure sensor for very low cost (essentially disposable), mass produced piece of medical equipment. The problem: this can't use any parts which aren't already ...
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-2 votes
1 answer
119 views

Developing a Medical Product Using AliExpress Modules

We are developing a medical product and we are using some modules that we got from AliExpress (www.aliexpress.com). They are really cheap and gave us the same results with the modules which we made ...
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5 votes
1 answer
160 views

What type of ultrasonic transducers are used in medical ultrasound devices?

When I search on DigiKey for ultrasonic transducers, all I get back is the circular transducers that are sold for the various DIY projects. i.e. the picture below: However, the "medical" ultrasound ...
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1 vote
1 answer
282 views

SMPS electrical noise issue

1I'm using class 2 medical graded SMPS in our device. So earth connection not recommended. When connecting SMPS to load (contains capacitive touch LCD), touch function is affected by SMPS noise. When ...
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8 votes
5 answers
2k views

Circuit for small level voltage detection (microvolts)

I have been working on a project lately which help in the detection myogenic potentials (of the levels of micro-volts). After studying from several places, I finalized the following test circuit. The ...
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0 votes
1 answer
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Circuit for high voltage pulses using raspberry pi PWM to drive a piezoelectric actuator

I am trying to engineer a device to separate red blood cells from blood plasma in 100mmx1mm capillary tubes using the raspberry pi GPIO pin PWM feature and a piezoelectric actuator. The pulses ...
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0 votes
2 answers
220 views

ECG electric design: 1 and 3 op-amp designs from a safety point of view

During the design of an ECG using an instrumentation and a differential amplifier, we can across this question: Comparing the one and three op-amp designs from a safety point of view: of the two ...
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5 votes
2 answers
1k views

Using optocouplers at the end of a twisted pair

I am designing a dumb "isolation box" that is to sit between a computer and medical data acquisition equipment. The purpose of this box is to inject power and to provide communications and digital ...
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1 vote
2 answers
351 views

Double ethernet magnetics for a passive medical application

I am designing medical data acquisition equipment that requires moderately fast data transfer. As part of the design we are using a custom 100BASE-T PoE architecture (and cabling) to the data ...
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0 votes
2 answers
171 views

Recording of sensory nerve evoked potential generated through skin-receptors [closed]

If we touch / give pressure to a skin, there are many mechano-receptors like meissner/pacinian corpuscles that produce action potential in neurons. I am in a need to detect those action potentials ...
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1 vote
0 answers
68 views

Medium Power Charge Pumps

I'm working on an MRI research project where I need to power my device with a single BNC cable. Internally my device needs 15V, -8.5V, 5V, 3.3V and 1.2V supplies. The 15V, -8.5V and 1.2V only need ...
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0 votes
2 answers
167 views

How to measure body temprature and HBR with just one IR transmitter and receiver

I want to measure body temperature and heartbeat rate only with a IR receiver and transmitter. How could I do that? Is it an accurate method? Or I have to use IR temperature sensor for this.
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Power supplies with medical safety approval

Regarding the data sheet of this SMPS power supply. In the first page it says: 2 x MOPP Medical safety according to AAMI/ANSI ES 60601-1:2005(R) and IEC/EN 60601-1 3rd edition Then I googled to ...
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5 votes
2 answers
797 views

Designing single fault safety into class I device

I'm trying to wrap my head around safety standards for electrical equipment. My device is medical, so for me section 8 of IEC60601-1 is what really matters to me, but it's kind of my understanding ...
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12 votes
10 answers
3k views

Is it practical for firmware to be uniquely identified in production

Are there systems available in large scale manufacturing that allow a unique serial number to be programmed into the firmware or some free memory space for each PCB that comes through? I've found ...
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0 votes
1 answer
264 views

Ambient Light cancellation on Pulse Oximeter

I'm trying to build a pulse oximeter using TSL2305 LTF sensor and 2 LEDs(Red and IR). The desired graph expected from the light are plotted correct but I want to know whether there should be any ...
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1 answer
377 views

Defibrillator energy?

Just been reading this where this statement is made: If the patient is in Ventricular tachycardia (VT) or ventricular fibrillation (VF) on the monitor, immediately apply the pads and shock the ...
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3 votes
1 answer
200 views

Patient Connection Radiated Emissions problem

The company I am working for is developing a patient-connected device intended to deliver Functional Electrical Stimulation to a connected user. We are currently struggling to pass the radiated ...
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1 vote
1 answer
96 views

Why do I need to keep Led drive and photodiode ADC supplies and traces separate in a pulse oximeter design

I've seen a couple of application notes recommend keeping led drive supply and ADC supplies separate. To me it seems that since the LED will illuminate the photodiode that ADC is reading anyway, ...
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4 votes
2 answers
140 views

Circuit Testing, Verification & Certification Standards for Biomedical Devices

Please note: I would have posted this question on HealthIT.SE but they are apparently now closed for business, and I believe this site is the next most appropriate place to ask this. I believe this ...
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1 vote
2 answers
2k views

How is this EEG circuit amplifying and filtering input correctly?

Several weeks ago I posted several|questions about a DIY EEG reader that I found on Instructables. To my surprise, it appears to actually be a fairly well-designed circuit. The main stages of this ...
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2 votes
1 answer
279 views

How do I choose a cable /cord, connected to mains part, that is compliant with IEC 60601-1 3rd ed.?

IEC 60601-1 is a standard for medical devices. It describes which are the requirements for the Means of Operator Protection and Means of Patient Protection, the current leakages and so on. I don't ...
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1 vote
2 answers
281 views

To what extent does an ADC solve noise along an analog circuit?

Please note: Although this question involves EEG, I don't expect anyone here to be knowledgeable in this area! This is a simple electronics question! I'm trying to understand the circuitry devised in ...
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0 votes
3 answers
202 views

Surface-Mount Prototyping (AXL 335 & SFH 7050)

I'm working on a senior project and I'm having some trouble prototyping with surface mount components. I know you can find SMT adapters out there for most SMT chips and components, but I've been ...
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3 votes
1 answer
813 views

Make an electronic Stethoscope

I've seen some kind of electronic stethoscope that can capture heart beat rate and filter it with so many other features. Main oscope of my questoin is about capturing heart sound. There is many ways ...
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