196. For a series AC circuit, _________ is not used as a reference phasor.

Draw a circuit diagram with a three-cell battery in series with an open switch, a resistor, an ammeter showing the current flowing from the resistor, and a fuse. Also, draw a voltmeter measuring the potential difference across the source.

Find the voltage difference between a and b using the node voltage method:

   2. Consider the following circuit (18 pts): 

2A) Use the node voltage method to find the voltage difference between nodes A and B for t<0 s. (3 pts)

A coil having an inductance of 6 H and an unknown resistance is connected in series with 
a resistor of 10 Ω to a 120 V dc supply. The time constant of the circuit is 300 ms. When 
steady state conditions have been reached, the supply is replaced instantaneously by a short-circuit. Determine the resistance of the coil, the current flowing in the circuit one second after the shorting link has been placed in the circuit, and the time taken for the current to fall to 10% of its initial value.