Block 4 - lecture 1 Flashcards
the two states of diode based semiconductor devices?
conducting (on) or not conducting (off)
how can a transistor be used to adjust voltage?
turning on and off quickly with specific timing.
the more time in the conducting state, the higher the voltage
BJT?
Bipolar junction transistor
what’s used to change the current that controls the transistor?
a control circuit
operating a BJT in the switched mode?
saturated (fully on) when the square wave input is high, then non-conducting (fully off) when it’s low
operating a BJT in linear (active) mode?
either full power or min power
equation for average power?
Paverage=Ton/T * max power
P=IV, P=V^2/R
name for the ratio “t on”/T?
the duty cycle (D)
what does the duty cycle represent?
the ratio of time that the BJT is in the saturated state
benefits of running a BJT in switched mode?
+less power lost through heating
-some losses from switching
Types of controlling devices?
- BJT (slow, cheap high currents)
- MOSFET (fastest, high voltages)
- IGBT (combination, high voltage and current, slowest)
electric motors?
electromagnetic devices that transfer electrical inputs into mechanical outputs
types of motors?
- DC motors
- AC motors
- Stepping motors
inputs used to change the motor performance?
- voltage (DC)
- frequency and voltage (AC)
- frequency of steps (stepper)
typical short term overloading capability of motors?
30% to 200%, if the supply can provide it
