1ftp://muhogr:email@example.com/ Medical InstrumentationApplication and Design,4th EditionJohn Wiley and Sons Ltd, Feb 2009, Pages: 713Basic Concepts of Medical InstrumentationBasic Sensors and PrinciplesAmplifiers and Signal ProcessingThe Origin of BiopotentialsBiopotential ElectrodesBiopotential AmplifiersBlood Pressure and SoundMeasurement of Flow and Volume of BloodMeasurements of the Respiratory SystemChemical BiosensorsClinical Laboratory InstrumentationMedical Imaging SystemsTherapeutic and Prosthetic DevicesElectrical Safety
35Elektrik akımı ve geriliminin insan için zararlı, öldürücü olma değerlerini, frekans özelliklerini de göz önüne alarak anlatın.(%20)Duyarlık elemanlarımızın cevaplarının zaman göre çıkışlarının: (giriş çıkış arasındaki gecikme var/yok, gecikmenin türü)zero-order (%5)firs-order (%5)second-order (%5) olma özelliklerini anlatın.EKG işaretlerinin algılanmasını, elde edilen işaretin genlik ve frekans özelliklerini, şeklini ve anlamlarını anlatın. (%20)Kan basıncını (mekanik-analog) ölçme yöntemini (ölçülen değerlerin anlamlarını belirterek) anlatın. (%15)Bioelektrik empedans tanımı, ölçmeleri, dijital terazide vücudun yağ, su değerlerinin belirlenmesi anlatın. (%20)Sadece üst tarafından erişilebilen 10 m derinlikte bir havuzunun içindeki suyun seviyesiini en güvenli şekilde ölçmek, ve display etmek için gerekli farklı iki sistemi tasarlayı, çizin, anlatın. Öneri-1(%5), Öneri-2(%5),
41Pulse oximetryThe probe contains two high intensity, monochromatic, light- emitting diodes, one emitting red light (660 nm) and the second infrared (940 nm) on one side and a photodetector on the other to measure the amount of light transmitted through the finger.
64Digital Capacitance Meter (1)Each units are: t seconds, R ohms, C farad and epsilon is a Napier's number (approx. 2.72). When VC reaches VC1, the time t1 can be expressed in following formure. (2)This means that the t1 is proportional to C. Thus the capacitance can be calcurated from charge time and any other fixed parameters.
70This audio frequency meter uses 555 IC as a monostable multivibrator (one-shoot trigger). A monostable multivibrator can act as a frequency-to-voltage converter because it produce a fixed pulse width, with the repetition rate/density is proportional to the triggering input frequency. Here is the circuit’s schematic diagram:For resistor R1, because it set the measurement range, it’s better to use a rotary switch to select different values for different ranges. For the ampere meter, you can use both analog or digital ampere meter. A cheap dual-slope ADC digital meter is suitable because its averaging characteristic, but a fast digital multimeter can also be used although it may show some uncertainty because of their fast sampling.
71This 1-kHz linear-scale analog frequency meter circuit uses the 555 as a pulse counter
74For this example, the discharge is underdamped (biphasic, also referred to as a Gurvich waveform) when the patient resistance is less than about 56Ω becauseRpatient+Rinductor=56Ω+10Ω=66Ω<Rcritical=67ΩIn this case, the waveform is underdamped and produces a biphasic (oscillating) waveform.If the patient impedance is higher than 67Ω, the waveform is overdamped (monophasic,also referred to as an Edmark waveform). In this case the inductor slows the rate of rise of the discharge current, reduces the maximum voltage applied to the patient, and shapesthe waveform to produce a damped sinusoidal waveform. The current delivered to thepatient gradually rises to a rounded peak and drops back to zero. The discharge currentpulse duration is about 2.5L1/C1, about 2.5 to 3.5ms for most defibrillators.DESIGN AND DEVELOPMENTOF MEDICAL ELECTRONICINSTRUMENTATION
75Figure 8.32 Schematic diagram of a damped sinusoidal waveform defibrillator capable of delivering energies of up to 320 J into a 50-Ωpatient load through a 5-ms Edmark (monophasic) waveform. Charge pushbutton SW2 energizes high-voltage transformer T1. C1 is charged through the high-voltage rectifier network D1–D4 and R1. Meter M1 is calibrated to yield an estimate of energy (in joules) delivered to the patient, assuming a load impedance of 50Ω. Defibrillation energy is delivered to the patient by simultaneously pressing on pushbuttons SW3 and SW4, which energize relay K1, which is used to transfer the defibrillation charge from capacitor C1 to the patient via pulse shaping inductor L1. R4 and R5 discharge C1 if the defibrillation buttons are depressed without a suitable load across the paddle electrodes or the
77Energy limitsA.C. defibrillator0.25 sec × 230 volts × (I Amps) = 450 watts-sec.Required requiredI = 7.5Amps.But preferable 0.01 sec. Pulses.Then I = 450/(230 × 0.01) = 175 A.This is too much to be supplied by household mains.
78DC Defibrillation (Fig. 12.10b) 1. Safety housings for electrodes–capacitor discharges only when the electrodes are makingfirm contact with the heart or chest wall.2. Two set of electrodes - not interchangeable sockets1. Internal 50–72 J (5–3 kV)3. Meter indicates Joules1. External 400J (7 kV).4. Charging time constant of 4 secondsM Ω × 16 μF2. (charging resistor)Takes about 16 secs. to charge to 4 kV.
79CAPACITIVE-DISCHARGE DC DEFIBRILLATORS MEDICAL INSTRUMENTATION Application and DesignFOURTH EDITION John G. Webster, EditorCAPACITIVE-DISCHARGE DC DEFIBRILLATORSA short high-amplitude defibrillation pulse can be obtained by using thecapacitive-discharge circuit shown in Figure In this case, a half-wave rectifier driven by a step-up transformer is used to charge the capacitor C. A good rule of thumb is to keep charging time under 10 s.
89A method which involves the measurement of bioelectrical resistive impedance (R) for the estimationof human body composition is described.This method is based upon the principle that the electricalconductivity of the fat-free tissue mass (FFM) is far greater thanthat of fat.Using an electrical impedance plethysmograph with a four electrodearrangement that introduces a painless signal (800 A at 50 kHz)into the body.FFM was assessed by hydrodensitometry and rangedfrom kg.Total body water (TBW) determined by D2O dilution and total bodypotassium (TBK) from whole body counting were 50.6 ± 10.3 L and167.5 ± 38.1 g, respectively..
92Uroflowmetry http://www.digitimer.com/urodynamics/urodynamics.htm The SEDIA F1 Flowmeter provides you with a convenient, cost effective and easy to use solution for portable uroflowmetry. Communication between the flow meter and your computer is via Bluetooth connection. The SEDIA software is easily installed on your Windows PC, allowing you to print reports from your own printer.Tepe idrar akım hızı erkeklerde 20 ml/sn, kadınlarda ise 25 ml/sn üstünde normal oalrak kabul edilir