What is Thevenin’s theorem
Used to simplify circuits
First calculate the open circuit voltage so treat it like a potential divider
Then calculate short circuit current which is like ignoring the 2nd resistor and calculating current
Then calculate equivalent resistance by using the current and voltage you calculated
Use the 3 things you found to draw an equivalent circuit with 2 leads going to the load or a volt meter
Different types of rectifiers circuit and their properties
Half wave, half of the energy wasted uses only 1 diode Voltage drops by 0.7v because of the diode
Full wave, voltage drops by 1.4v because of the 2 diodes
Smoothing capacitor can be connected to both circuits goes in parallel with the load so when the rectifier cant provide current the capacitor does
https://imgur.com/a/oxdKE4k
In charging and discharging capacitor equation what do the symbols mean
Vc = target voltage
Vo = supply voltage
How to know if a capacitor is charging or discharging
Charging capacitor
If a the two ends of the capacitor are connected to a power supply then its is charging, needs to have a resistor in the way or too much current will be drawn
Discharging capacitor
If the two ends aren’t connected to a power supply but instead connected across a load then it will be discharging giving its power to the resistor
So if the resistor is in series it is charging, if in parallel it is discharging to the resistor
Astable and monostable circuits
Astable shmite not gate with resistor in parallel and in series capacitor before
Monostable, capacitor and resistor in series with switch connected to capacitor in parallel and a not gate coming of between the capacitor and resistor. While the switch is closed it is in the stable state when it opens is the unstable state. As the capacitor slowly charges (when the switch is open) because the resistor is limiting the current the not gate activates when the voltage of the capacitor reaches the activation voltage
https://imgur.com/a/KgW4ioS
Difference between astable 555 and monostable 555
monostable will have a switch connected to pin 2 since you want a way to activate it
Astable does not have a switch since it doesn’t need activating switches between the 2 states
How does the monostable 555 work
https://imgur.com/a/9gQnt3q
pin 7 discharge
pin 6 threshold monitors voltage
pin 2 trigger
when it is triggered the out put goes high ,pin 7 disconnects so the capacitor can charge when it reaches 2/3 of the voltage pin 6 detects it and turns of the output and reconnects pin 7 and the capacitor discharges.
SR flip flop circuit and truth table
Uses 2 nand gates the outputs feeding back into the other gate
First output is Q, second output is not Q
First input S, second input R
input 0 0 is unusable state
whatever the inputs are the corresponding output is the opposite
input 1 1 is remembered state and the outputs will be the same as before
How does a D type flip flop work and the versions for up counter and down counter
Active high clock (triggers on rising edge) D pin gets copied to Q and not Q has the opposite
D and not Q are connected because you want the output to change every clock pulse
Q is the output and connects to any LEDs
Down counter
Q connects to the clock
So on the very first clock pulse the outputs of every counter goes high and so you start with all the bit high
UP counter (the weird one)
Not Q connects to the clock
What does a saturated transistor mean
The collector and emitter are shorted because the base has current. So the transistor will have a voltage of 0 across it because its acting like a wire with 0 resistance, and resistor will have all the voltage across it
Op amps circuit
Both have resistor called Rf connecting the output to the inverting pin and have a resistor called R1 connected to inverting pin
Inverting op amp
power connected to inverting pin and has a resistor called R1 in the way. Non inverting pin connected to gnd
Non inverting
Power connected to non inverting. Inverting connected to gnd with resistor in the way
Op amp characteristics
Open loop gain
The gain with no resistors attached want it to be ∞
Input impedance
Resistance of the input want it to be ∞ so no current is drawn
Output impedance
Resistance of the output want it to be 0 so it can provide as much current as needed
Infinite slew rate
Want it to be ∞ so the output changes as quick as possible. Higher the slew rate the quicker the output changes
number of opamps needed for ADC flash converter
Signal conversion
2^n n being the number of bits after the priority encoder
this includes the overflow opamp
how does a strain gauge work
Instrumentation
gets stretched, the resistance of the wire depends on the length of the wire so when it gets stretched the resistance increases
What is a bridge circuit
Instrumentation
used to cancel out any changes in power supply voltage or resistance changing because of a random factor. It is 2 voltage dividers and the V out is the difference in voltage between the 2 dividers. Where one of the voltage dividers is a dummy to cancel out any unwanted changes
What is a difference amplifier and equation and circuit
Instrumentation
Compares the 2 inputs and amplifies the difference. It amplifies the inverting and non inverting inputs by the same amount then since the inverting is negative and the non inverting is positive they combine and it subtract. So positive input minus negative input and amplify by the gain. The gain being Rf/R1 no need for the negative sign(also on equation sheet)
Circuit diagram is a inverting amplifier resistor set up for the inverting input and a voltage divider for the non inverting input, going from Vin to 0V, with the same resistor values
