Random Flashcards
(18 cards)
Kirchoffs current law
Current going into a closed circuit region = current flowing out
Currents flowing out of any closed region of a circuit sim to zero
Charge can not accumulate
Kirbb Co offs voltage law
Sum of voltage changes around any closed loop is zero
What’s a branch
Something coming out of a node
E.g. you have a node with 3 wires coming out
For a circuit with N nodes and S sources, how many simultaneous equations?
N-S-1
What’s an ideal voltage source?
Maintains same value of V for all currents. Vertical line with infinite gradient on I/V graph
What’s an ideal current source?
Maintains the same value of I for all voltages. A horizontal line on I/V graph with zero gradient. I is negative?
Components in series share the same…
Current
Components in parallel share the same…
Voltage
What’s RMS
Value of an ac voltage or current that’s the equivalent dc voltage or current that dissipates the same power in a resistor
Open circuit voltage
If I = 0
X intercept 0
V oc = V Th
Short circuit current
If v = 0
Y intercept = x
I sc = - V Th/ R Th
Thevenin resistance
dI/dV = 1/R Th
Max power when
Rth = RL
When is thevenin applicable?
When you have fixed voltage/current sources
What happens when you make the time constant bigger than the period?
Wave flattens
Bigger time constant than period but CR circuit
Wave form is very similar to original as it doesn’t have time to charge and discharge
Corner frequency (p) =
1/RC
1/tau
What’s a low pass filter?
Allows low frequencies to pass but attenuates (makes smaller) high frequencies
