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Electronic Technician Certification Program
BASIC MATH ReviewSeptember 09, 2020
1. Add ( 250 x 103 ) + (1.5 x 106 ) =
2. Add ( 250 x 10-6 ) + (1.0 x 10-3 ) =
3. Subtract 400 x 103 from 2.0 x 106 =
4. Multiply (2.0 x 104) by (30 x 102) =
5. Divide (500 x 105) by (25 x 102) =
6. Multiply (25 x 100) by (2.0 x 103) =
7. Divide (100 x 10-6) by (2.5 x 10-4) =
8. Find the reciprocals for 106 and 10-4
9. Square (2.0 x 102) =
10.Find square root of (9 x 106) =
11.Find square root of (40 x 103) =
Make the following conversion:
1. 22mA = microA
2. 1500kHertz = Mhertz
3. 1.5k =
4. 2.5W = mW
Electronic Technician Certification Program
Metric Prefixes
Prefix Symbol Scientific Notation
tera- T 1012
giga- G 109
mega- M 106
kilo- k 103
milli- m 10-3
micro- 10-6
nano- n 10-9
pico- p 10-12
General purpose Resistor4-bands
Precision Resistor5-bands
GENERAL PURPOSE RESISTOR COLOR CODEFirst band Second band Third band Fourth band
Color First Digit Second Digit Multiplier ToleranceBlack - 0 100 -Brown 1 1 101 -Red 2 2 102 -Orange 3 3 103 -Yellow 4 4 104 -Green 5 5 105 -Blue 6 6 106 -Violet 7 7 107 -Gray 8 8 108 -White 9 9 109 -Gold - - 10-1 +/-5%Silver - - 10-2 +/-10%None - - - +/-20%
Electronic Technician Certification Program
Electronic Technician Certification Program
PRECISION RESISTOR COLOR CODEColor First Second Third Multiplier Tolerance
Digit Digit DigitBlack - 0 0 100 -Brown 1 1 1 101 +/-1%Red 2 2 2 102 +/-2%Orange 3 3 3 103 -Yellow 4 4 4 104 -Green 5 5 5 105 +/-0.5%Blue 6 6 6 106 +/-0.25%Violet 7 7 7 107 +/0.1%Gray 8 8 8 108 -White 9 9 9 109 -Gold - - - 10-1 -Silver - - - 10-2 -
Electronic Technician Certification Program
brown
red
orange
silver
red
violet
gold
gold
green
white
violet
gold
blue
What is the value and tolerance of the following resistors:
red
green
red
brown
green
Electronic Technician Certification Program
TEST EQUIPMENTS:
• DMM (Digital Multimeter)
Measure:• DC and AC (Vrms) voltages
• DC and AC (Irms) currents
• Resistance (Ohm)
• Continuing
Option:
• Capacitance
• Diode
• Frequency
To measure current HI Lead must connect to this site
Electronic Technician Certification Program
In the above formulas E = VOLT I = AMPERE R = OHM
Electronic Technician Certification Program
DC SERIES CIRCUIT
A BR1
50
R3150
R2
100
60V
E
C
I
Solve for:1. Total resistance Rtotal2. Current I3. Voltage at B4. Voltage at C5. Voltage across R1 (VAB)6. Voltage across R2 (VBC)7. Voltage across R38. Power dissipated in R19. Power dissipated in R210. Power dissipated in R3
VOLTAGE DIVIDER LAW:• Calculate VC= (E x R3) / (R1+R2+R3)= 60 X 150 / (50+100+150)= 30V• Calculate VB= E x (R2+R3) / (R1+R2+R3)= 60 X (100+150) / (50+100+150)= 50V
Electronic Technician Certification Program
30V
ER1 120 R2 200 R3 300
I I1 I2 I3
DC PARALLEL CIRCUIT Total current I = I1 + I2 +13 Equivalent resistance Req = 1 / (1/R1 +1/R2 + 1/R3) Only two resistance in parallel
Req = (R1 x R2 ) / (R1 + R2 ) The voltage is the same
For the above circuit, find:
1. Equivalent resistance Req
2. Total current I
3. Current I1
4. Current I2
5. Current I3
6. Voltage across R2
7. Power dissipated in R3
Electronic Technician Certification Program
I
I1 I210V
ER1 50 R2 50
• ONLY TWO RESISTORS IN PARALLEL• CURRENT DIVIDER LAW
• Req = (R1 x R2) / (R1 +R2)• Current divider law:• I1 = I x R2 / (R1 + R2)• I2 = I x R1 / (R1 + R2)
THE END
