201.
The purpose of using flux in soldering is to.......
A
Increase fluidity of solder metal
B
Feel up gaps left in a bad joint
C
Carbon steel
D
Prevent oxides forming
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The purpose of using flux in soldering is to.......
Increase fluidity of solder metal
Feel up gaps left in a bad joint
Carbon steel
Prevent oxides forming
A soldering iron bit is made of.......
Brass
Tin
Steel
Copper
Soldering iron is made of wedge shape in order to......
Apply high pressure at edge
Retain heat
Retain solder
Forge welding
When brazing is carried out.........
A joint is made between two parts by molten spelter
The edges of the joint melt and run together
Spelter forms an alloy with the flux
Flux prevents the work from melting
The temperature range for soldering process is.......
40°C to 100°C
180°C to 250°C
300°C to 500°C
600°C to 900°C
The temperature range of brazing process is.........
150°C to 250°C
250°C to 450°C
500°C to 700°C
700°C to 900°C
When an SCR is turned on, the voltage across it is about ..........
10 V
0.1 V
1V
zero
An SCR is a ……………….. triggered device
Current
Voltage as well as current
None of the above
Voltage
An SCR behaves as a ……………. switch
Bidirectional
Mechanical
None of the above
Unidirectional
AC power in a load can be controlled by connecting
Two SCRs in parallel
Two SCRs in parallel opposition
None of the above
Two SCRs in series
We can control a.c. power in a load by connecting …………
Two SCRs in parallel
Two SCRs in parallel opposition
None of the above
Two SCRs in series
An SCR has ………….. semiconductor layers
Three
Four
None of the above
Two
An SCR has …………….. pn junctions
Three
Four
None of the above
Two
An SCR is a solid state equivalent of …………….
Pentode
Gas-filled triode
Tetrode
Triode
An SCR is sometimes called …………
Diac
Unijunction transistor
Thyristor
Triac
If firing angle is increased, then the output of an SCR
Is increased
Is decreased
None of the above
Remains the same
If firing angle in an SCR circuit is increased, the output …………
Is increased
Is decreased
None of the above
Remains the same
An SCR is turned off by …………….
Reducing gate voltage to zero
Reverse biasing the gate
None of the above
Reducing anode voltage to zero
A single phase ac - dc converter is also known as
inverter
chopper
regulator
rectifier
In AC supply, an SCR can exercise control over
Negative half-cycles only
Both positive and negative half-cycles
Positive or negative half-cycles
Positive half-cycles only