ECT 122 Week 4 iLab #1
DC power supply
1. What is the relationship between conductance and resistance? They are the reciprocals of one another.
2. What is the symbol for mhos? ______upside down omega sign (Ω)___
3. What other unit, other than mhos, can conductance be measured in? What is its symbol? Siemens, S
4. What is the total resistance of a circuit with three parallel resistors with the values below?
Gt= G1+G2+G3= 0.5mS+0.25mS+0.75mS= 0.0015 x 10^-3= 1.5mS
Rt= 1/Gt= 1/1.5mS= 667Ω
5. Use the reciprocal method to calculate the total resistance of the circuit below.
Rt= 1/(1/R1+1/R2)= 1/(1/2.2kΩ + 1/3.3kΩ)= 1320 x 10^3= 1.320kΩ
6. Calculate the total resistance of the circuit above using the product-over-sum rule.
Rt= R1(R2)/R1+R2= 2.2kΩ(3.3kΩ)/2.2kΩ+3.3kΩ= 1320 x 10^3= 1.320kΩ
7. Construct the circuit above on the breadboard. Do not connect the power supply. Using the handheld DMM, measure the total resistance of the circuit.
How do the calculated and measured values compare? They were the same.
8. If using ELVIS, repeat step 7 using the ELVIS DMM. If the measurements do not match, check all connections and repeat the measurement. If NOT using ELVIS, skip to step 9.
9. What is the equivalent resistance of the following circuit? What is the total current? What is the value of current in each branch? Do not make any calculations on paper. Do the problem by inspection (in your head).
Rt= 10kΩ/2=5Ω It= 2mA Ir1= 10V/10kΩ=1mA Ir2= 10V/10kΩ=1mA
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