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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

What is the RMS amplitude (root mean square)?

The amplitude a DC signal would need to be in order to provide the same average power peak amplitude