Flashcards in Electricity Deck (59):

1

## What is a circuit?

### Collection of elements or a collection of elements and signals that are connected together for purposes of modifying input signals to obtain other desired responses

2

## In a circuit picture of a battery, which is the + positive side of the battery?

### The long bar

3

## What is the type of amplifier used in physiology?

### Differential Amp (Type 2)

4

## What kind of circuit does not allow for work ?

### Short circuit

5

## What is the definition of an electric current?

### The flow of charges per unit time

6

## What is the unit of charge?

### Coulomb

7

## What is the MKS unit of electric current?

### Ampere

8

## How much does 1 ampere represent?

### Flow of one Coulomb per second

9

## How much does a negative coulomb equal?

### 6.25 x 10^18 electrons

10

## How is voltage measured?

### Always between 2 points

11

## What is V = IR

###
Ohm's Law

(voltage = current x resistance)

12

## What is Darcy's law?

### Q = P / R

13

## What is the difference signal and flow signal of electrical measurements?

###
DS : Voltage V (volts)

FS : Current I (amperes)

14

## What is the difference signal and flow signal of hydraulic measurements?

###
DS : pressure P (dynes / cm^2)

FS : flow V (cm^3 / sec)

15

## What is the difference signal and flow signal of thermal measurements?

###
DS : temperature T (*C)

FS : heat flow q (watts)

16

## What is the difference signal and flow signal of concentration measurements?

###
DS : solute concentrations C (mg/mL)

FS : solute flow Q (mg / min)

17

## What does DC stand for?

###
direct current

(consistent straight line about non zero number)

18

## What does AC stand for?

###
alternating current

(varies around zero)

19

## What type of current does the cardiovascular system use?

###
DC + AC

(varies around non zero number)

20

## Arterial blood pressure waveform is based on what 2 measurements?

###
Mean pressure and pulse pressure

21

## When is mean circulating filling pressure measured?

### When flow is stopped, therefore the heart is stopped, and thus value should be very close to 0

22

## What is frequency?

### Number of variations / sec

23

## What is Coulomb's law?

###
F = k (q1 x q2 / d^2)

f = force , q = charge strengths

d = distance between charges

k = coulomb's constant

24

## What does coulomb's law measure?

### relationships of charges

25

## What is formula for frequency?

### f = 1/T

26

## When using the "right hand rule" in magnetic fields, what does thumb point to and what does fingers point to?

###
Thumb points to positive end.

Fingers point towards magnetic field

27

## What is the equation of power?

###
P = I V

power = current x voltage

28

## What does Kirchhoff's Voltage law state?

###
The sum of the voltage variations around a loop is zero

(Rt = R1 + R2 + R3)

29

## What type of series system do humans have?

### Closed system but not series system

30

## What are the only things in human body that can vary resistance?

### Arterioles

31

## What is Kirchhoff's Current Law?

### Sum of all currents that converge on a node will be zero

32

## When adding parallel resistances, is the total resistance reduced or increased?

### Reduced

33

## V = 0 when multiplied cross products are equal to each other ( R1 x R4 = R2 x R3). This is known as what?

### The wheatstone bridge , or the balance equation

34

## When is the wheatstone bridge used ?

### Used in pressure transducers

35

## What is a transducer?

### device that converts one form of energy to another form

36

## The ratio of the change in an electric charge in a system to the corresponding change in its electric potential is known as what?

### Capacitance or compliance

37

## T or F : Capacitors can hold charges and keep those charges separated.

### TRUE

38

## When parallel capacitors are placed in a circuit, are they additive or subtractive?

###
Additive

Ct = C1 + C2 + C3

39

## Parallel capacitance is dependent on what?

### The area of the plates and the distance between the plates.

40

## What is the equation of Capacitance?

### C = kEo x (A/d)

41

## Decreasing the distance between the plates will do what do capacitance?

### They will become much more compliant

42

## What major organ in the human body relies heavily on parallel capacitance?

### Lungs

43

## What type of capacitance is not found in the human body?

### Series capacitance

44

## Inductors, or inertance, is what?

### Measure of the pressure gradient in a fluid required to cause a change in flow-rate with time

45

## What is the major driving flow in hemodynamics?

### Blood

46

## What do inducers do?

### They try to resist current change in the circuit

47

## What type of inductance systems are most circulatory systems?

### Parallel inductance systems

48

## T or F: Various parts of the human body have different types of resistance?

### TRUE

49

## What is the capacitive reactance equation?

###
Xc = 1 /

2 (pi) f C

50

## If you have poorly compliant lungs, what kind of ventilation to you need to give to the patient?

### High frequency ventilation because the higher the f, the less the reactance

51

## What is the phase(time) difference that results from the human physiological system?

### 90 difference

52

## What is impedance?

### The sum of resistance, capacitive reactance, and inductive reactance taking the phase contribution of each into account

53

## What is the formula for impedance?

### Z = square root (R^2 + (Xl - Xc)^2)

54

## Why is the baseline heart rate between 60-70 bpm?

### Because the compliance and inertia of the heart cancels each other out, therefore it is the moment at which it is most efficient

55

##
What sizes do the bandwidth filters come that are used in accordance with the AHA?

What are these filters called?

###
0.5- 100 hz

Band pass filter

56

## A main source of EKG interference is what?

### 60 cycle EKG

57

## What does a band reject(notch) filter do?

### Cuts out many bands of frequencies

58

## What is the peak amplitude?

### The maximum amplitude in either the positive or negative half cycle

59