MODULE 1 : FUNDAMENTALS OF
ELECTRONICS EXAM 1
1. Discuss the relationship of voltage, current and impedance in an electrical circuit
(Ohm's Law).
*V = I/R*
*HIGH* lead impedance ∴ *LESS* current with each output ∴ *EXTENDED*
pulse generator life
*LOW* lead impedance ∴ *MORE* current with each output ∴ *DECREASED*
pulse generator life
2. Define voltage, current, resistance, energy and charge.
1. *VOLTAGE*
i. The *electrical force* that *makes current move* through a *conductor*
2. *CURRENT*
ii. The *rate of flow of charge* in an *electrical circuit.* This is measured
in *amperes and in a pacing circuit in milliamperes (mA).*
3. *RESISTANCE*
iii. *Opposition to the flow of current* through a *conductor: measured in
ohms.*
4. *ENERGY*
iv. The *active force (work) of the pacing stimulus* and is expressed in
*microjoules.* It can be *calculated from the voltage and the charge
(current multiplied by the time) or voltage x current x time.* It is an
*index of the battery drain* with each output stimulus.
5. *CHARGE*
v. The *quantity of electricity that has flowed.* It is measured in
*coulombs and is the product of the current multiplied by the time.*
3. Describe the relationship between pulse amplitude and pulse width (strength
duration curve).
1. *Pulse width* is the *duration of the applied stimulus* (spike), measured in
*milliseconds (ms).*
2. Pacemaker *output* is usually *defined in terms of voltage (pulse amplitude) and
milliseconds (pulse width).*
3. Pulse width is *measured from the leading edge to the trailing edge, termed
pulse duration.*
