Question

In this Lab you would connect resistors in various combinations then use the multi- meter to measure various currents and voltages. I have copied the schematics of the various circuits from the lab and completed portions of the data table with hypothetical (but highly probable) answers. Your task is to complete the data tables and answer the following questions. The value of a resistor can be determined by reading the colored stripes on the resistor. The color codes are given below. Note that there is a tolerance. Very seldom are resistors manufactured to exact specifications (it's too expensive!). The percent error = 100 * (Coded value - measured value)/Coded Value. 2nd Digit 1st Digit No. of Zeros Tolerance Black 0 Brown 1 Red 2 Orange 3 Yellow 4 Green 5 Blue 6 Violet 7 8 White 9 Fourth Band None 20% Silver 10% Gold 596 Red +296 Gray Example: A resistor coded Red, Brown, Blue, Silver has a value of 2.1x106 2. This would be + 10%. The red is the 2, the brown is the 1, and the blue means to by 1,000,000 (1x106). The silver means + 10%. Q1: What would be the colors of the following resistors? A) 120 N = Brown (1), Red (2), Red (2) = 1.2x102 B 240 S2 = C) 440 22 =

Answer 1

1) From the table using the colou values we have

B) 240 ohm = red (2) , yellow(4) , red (2) = 2.4 X 10 ² ohm

c) 440 ohm = yellow (4) , yellow(4) , red (2) = 4.4 X 10 ² ohm

2)

Resistance R (ohm)	Voltage V (Volt)	Current I (mA)
R1 = 200	v1 = 1.5	I 1 = V1/R1 = 7.5
R2 = 100	V2 = 0.75	I 2 = V2/R2 = 7.5
R3 = 100	V3 = 0.75	I 3 = V3/R3 = 7.5
R12 = 200 +100 = 300	V12 = 1.5+0.75 = 2.25	XXXXXXXXXX
R13 = 100 +100 = 200	V13 = 1.5+0.75 = 2.25	XXXXXXXXXX
R123 = 200+100+100 = 400	V123 = 1.5+0.75+0.75 = 3.0	XXXXXXXXXX

2) R123 = R1+ R2 +R3 as they are in series hence

R123 = 200 +100 +100 = 400 ohm

3) V 12 = V1 +V2,

LHS V12 = 2.25 V

RHS = V1 +V2 = 1.5+ 0.75 = 2.25 V

The potential in any series circuits is additive in nature.

4) The current I2 = V2/R2 . this relationship is taken from the ohm's law . where the potential across V2

putting the value we get I2 = 0.75/100= 7.5 mA

5 ) The same value of current illustrates that the series current is same throughout the circuit