Electricity Flashcards
Defined as the effects produced by moving charges
Electricity
Positively charged contain _______ prótons than electrons
More
Negatively charged contain _______ prótons than electrons
Less
Fundamental principle of charge interaction
A positively charged object will attract a negatively charged object
If the charge is let loose, it would move (_____) and if we hold it still it has ______
Kinetic, potential energy
The unit of electrical potential
Volt
Defined as the amount of charge flowing per unit of time
Current (I)
An ______ of current corresponds to 1 coulomb of charge per second
Amp
Materials I which charges can easily move are
Conductors
Most are no metals and generally are not good conductors except graphite
Insulators
To be a good ______, electrons must be able to move easily from one atom to the next
Conductor
The energy required to push electrons through a material
Resistance
Resistance is measured in
Ohms
Reciprocal or resistance
Conductance
The closed path through a charge flows is
Electric circuit
An electrical circuit in which the current flows in one direction only
Direct current (DC)
An electrical circuit in which the current reverses its direction in a periodic fashion
Alternating current (AC)
A situation in a circuit where the normal resistance of the circuit is bypassed by a low resistance path resulting in a large current
Short circuit
The product of volts and amps
Electrical power
Power is measured in
Watts
Power =
Energy/time
Energy =
Power x time
Large amount of current conducted through a patients skin or other tissue. Injury depends on amount and duration of exposure
Macro shock
Delivery of small amounts of current directly to the heath. Very small currents can produce vfib
Microshock
what provides a low resistance pathway for leakage current and constitutes the major source of protection against microshock in the electrically susceptible patient
the ground wire on a piece of equipment
Never _______ touch an electrical device and a saline filled central venous pressure cath or external pacing wires
simultaneously (wear rubber gloves)
macroshock accepted as max harmless current intensity
5mA
macroshock threshold of preception
1mA
microshock vfib
100microamp
electric devices with one narrow prong and one wide prong
polarized plugs
narrow prong is for
high potential
wide prong is for
low potential
Third prong ground plug if a high potential wire comes into contact with the case, the current will flow directly through _______, instead of through
the third prong instead of through your body
GFCI
Ground fault circuit interrupter-used in circuits near water, interrupts current if leak present completely, not good for life saving devices in OR
How are electrical systems isolated from the grounded electrical supply?
isolation transformers
Rely on magnetic inductance to transfer a current from the grounded electrical system to an ungrounded secondary system without the two systems physically contacting each other
Isolation transformers
Isolation tranformers have no direct connection to
ground which prevents shock
if live wires make contact with a ground, the ungrounded system now becomes a grounded system known as a
fault
Device that alarms when a fault in an ungrounded system occurs
line isolation monitor
alarm set point for a line isolation monitor is usually between
2 and 5 mA
If alarm is above 5mA
is likely true fault and unplugging each piece of equipment will identify the faulty piece and needs to be removed
what does the line isolation monitor not provide protection from?
microshock
