Ohmers Law Flashcards
Ohms Law
V=IR
Voltage =current x resistance (impedance)
Define voltage
Electromotive force or the force that drives electron flow
Define current
Flow of electrons
Define resistance
Resistance to current flow measured in ohms=impedance
Furmans formula
E=IR
E represents electromotive force
Define series
Beginning of one resistance is connected to the end of another
Formula for sum of resistances
R1+R2=total resistance
What type of lead issue does series resistance issue indicate ?
Lead fracture or loose set screw (increased impedences)
State how to determine voltage drop across a resistance
Determine the ratio of R1 to R2 to determine the percentage drop across each point
When are resistances said to be in parallel?
Resistances are said to be in parallel when ALL resistances are connected to the SAME point
List the formula for parallel resistances
R1 x R2/R1+R2
Give an example of resistances in parallel
Lead insulation defect (low impedance)
Does a lead fracture cause an increase or decrease in impedance?
INCREASE in impedance
Does a lead insulation defect cause an increase or decrease in impedance?
DECREASE
List normal lead impedance
400-600 ohms
Do PPMs use constant voltage or current?
Constant voltage ppm
Constant current for most temp pacers but some are constant voltage
To what does the term Load refer?
Impedance or resistance applied to a circuit
Is a system with a small load applied to a circuit considered constant current or constant voltage?
Constant current
Is a system with a large load considered to be a constant current or constant voltage device?
Constant voltage
Give an example of series resistance defect
Lead fracture ( high impedance)
