1.Basic knowledge of resistors

1.1 Resistors and Ohm’s law (how resistors function in circuits)

Typical passive components

・Resistors
・Capacitors
・Inductors (coils)

Ohm’s law is applicable to resistors

Possible usage of resistors under Ohm’s law.

・Deciding voltage
・Deciding current
・Measuring current
・Consuming power（converting electricity to heat）

Series or parallel resistors and voltage

V_out　= R₂/(R₁+R₂)
I= Vin/(R₁+R₂)
I= I₁= I₂

In series, voltage is proportional to the resistance

I= I₁+ I₂
V_out= V₂ = V₁ = Vin
R₁：R₂＝I₂： I₁

In parallel, voltage is the same on each resistors

Current is negatively proportional to resistance

1.2 Resistor marking and E series

The resistive value is expressed in 3 or 4 digit numbers following E-series. E-series are geometric progression series and depending on how many numbers used between 1 and 10, they are called E12, E24, and E96 series.

E12 series is a geometric progression

¹²10ⁿ　Substitute “n”with 0…11, and you get
1.0, 1.2, 1.5, … 8.2,
12 values with same ratio.

E24 series adds a number in between each of the E12 series, making them 24 numbers. ²⁴10ⁿ

Resistance value is expressed in 3 or 4 digit alpha numeric number on top of the products unless the surface is too small to mark.
⇒Significant figures are expressed in E series.

Additional explanation：Examples of resistance value expression

Chip resistors currently ranges from mΩ（milliohms）to MΩ（mega Ohms). Using the power of 10 and E series, resistance value is expressed as follows. The number of digits changes depending on the size and resistance value(For details, refer to the each product series. E-series are described on page 7 of the catalogue. )

Resistance value range and units

E6, E12, E24 series has 2 significant figures　
Last digit is n of 10ⁿ
n=1 ⇒10¹=　 10
n=2 ⇒10²= 100
n=3　⇒10³= 1000
R means decimal point under 10Ω

E96 series has 3 significant figures
Last digit is n of 10ⁿ
n=1 ⇒10¹=　 10
n=2 ⇒10²= 100
n=3　⇒10³= 1000
Under 1Ω, numbers after decimal point is expressed in 3 digits after R