Lectures 7-8 Flashcards
V out =
A OL X ( V p - V n ) = A OL X V diff
Open loop gain X p.d. difference
An op amp operating in its linear region avoids
saturation
A voltage follower important as
the power source of V in only needs to supply a little power, whereas the output can drive a power-hungry load, where the op-amp provides the power.
An inverting amplifier has the power supply connected to which node
the power supply is connected to the negative node.
Inverted is bad - negative
A non-inverting amplifier has the power supply connected to which node
the power supply is connected to the positive node.
Non-inverted is good - positive
A negative sign for voltage gain means that in relation to the input signal
the output is out of phase/180 degrees phase shift
What happens if your output voltage is larger than the power supplies to the op amp?
The output will be saturated
In a voltage follower non-inverting op-amp, V out = ?
V in
Difference between negative feedback closed loop compared to a voltage follower closed loop is
that R f (the resistor that is on the feedback branch) will not be there so R f is going to be 0, as it is just short circuited
R in for the voltage follower is —- because …
Infinity because the closed loop wire has not got an external connection so is just stated as R in = infinity, as its an open circuit.
No current will flow through an open circuit
Considering R f and R in for a voltage follower non-inverting op amp circuit, what would be the A CL?
A CL = 1
Rf / R in = 0/infinity = 0.
Where does the step up in power come from in a voltage follower non-inverting op amp circuit?
The output voltage is the same as the input, but the op-amp provides the step-up in power
Voltage comparator is when you compare
the V in and V out across an op amp
V out equation for an open loop op amp circuit
V out = A OL X ( V p - V n )
V out equation for an open loop op amp circuit
V out = A OL X ( V p - V n )
V out = open loop gain X p.d between the two input signals
