Mod 4, 5, 6 Flashcards
What is a Switch
A switch consists of an actuator and one or more sets of contacts. The contacts are opened or closed by the physical movement of the actuator
Single-pole, single-throw
single input contact and a single output contact.
Single-Pole, Double-Throw
single input contact and two output contacts.
Double-Pole, Single-Throw
two input contacts and a single output contact associated with each input contact.
Double-Pole, Double-Throw
two input contacts and two output contacts associated with each input contact.
Alternate Action Switch
remains in its free or operating position indefinitely until released.
Momentary Contact Switch
returns to its free position immediately after the operating force is removed.
Rotary Switch
contain a shaft actuator that is rotated to open or close the contacts
Switch Gangs
is any number of independent switches whose actuators are linked mechanically forcing them to act simultaneously.
Microswitches
will open or close a circuit with a very small movement of the tripping device (1/16 inch or less).
Derating Factors
Circuits containing incandescent
Inductive circuits have magnetic energy
Direct-current motors will draw
what is Relay
sets of contacts that are opened or closed by the electromagnetic action of a coil,allow a low power control voltage operate a high power switch
The minimum amount of current required to activate a relay ?
Pick up current
normally closed contact are closed in
no operation position
A Diode with both ways resistance is probably
shorted
what is the is a circuit breaker designed to protect
wire
The Cathode in a Diode is positive or negative
negative
the bias voltage in a silicon semiconductor is ?
0.7 volts
the 3 connectors on the transistor is
base emitter collector
main different in a fuse and circuit breaker
circuit breaker can be reset
a secondary cell can be recharged
yes, a primary cant
to increase the voltage of 2 batteries you should hook them in parallel ? false or true
false
the negative part of a batteries is known as ?
Cathode
the closed circuit voltage of a battery we always be higher than the open circuit voltage true or false
false
to increase the current output of 2 batteries you should
connected in parallel
if a transistor is on what is the voltage between the base and emitter
0.7 volts
what is rectifier Diode use for
These circuits convert the AC power to DC used by the equipment
zener diodes are use to
keep voltage constant
Seven Steps for Troubleshooting
1) Identify the problem
2) Gather all types of data
3) Get a plan of attack
4) Find the fault
5) Repair or replace the component
6) Test the system after the repair
7) Paperwork, paperwork, paperwork
Discharge capacity
Is a measure of the energy available from the cell, expressed as a product of current and time
Ah or mAh
A batteries are consider discharge when the voltage drop to ?
1.2 volts
Nickel-Cadmium Cells can be recharged how many times ?
500 or more
cells types
primary - one use
secondary -rechargeable
Lead-Acid Cells
may be wet or dry. Wet cells use two different forms of lead as electrodes in a weak sulphuric acid electrolyte
Open circuit voltage (OCV)
is the voltage measured across a battery when no load is applied.
closed circuit voltage is
voltage measured across a battery when a load is applied
What does the term closed-circuit voltage mean in regard to a battery?
the voltage measured while a load is applied to the battery
Equation to calculate the length of operation of a battery
time = (ampere-hour)/current
What happens to the internal resistance of a battery as it becomes discharged?
increases
What is a positively charged electrode called in a battery
anode
