Resistor color code

A resistor is the most important electrical component in almost every electronic circuit, it can limit current to any load such as led, transistor, opamp, etc. We must read resistor color code if we want to know the resistive value, tolerance, temperature coefficient. Resistors have different color bands (3,4,5,6) the more color bands the more resistor's information.Now let's start with 3 bands resistor color code.

The above resistor has only 3 bands First digit, Second digit, and multiply. A 3 bands resistor color code has fixed +/-20% tolerance that means if color code value is 1,000 ohms the real life resistive value may be +/- 200 ohms. 
4 band resistor color code

A 4 bands resistor color code has tolerance value color strip, the resistor on an above picture has 5% tolerance. This type of resistor uses in a regular circuit such as television,radio,washing machine.

5 bands resistor color code

A 5 bands resistor color codes have third digit color bands.
1(first digit) 0(second dig…

2.5 watts lm 380n amplifier with stable wiring diagram.


1 Wide supply voltage from 10 to 22 volts so you can use battery power.
2 Use only 8 parts to make jobs done.
3 High bandwidth 100khz
4 Low distortion no more than 3% at 2 watts (not 10% thd at full power like commercial amplifier spec )

Lm380n is old but still good sounding ic if you can eliminate oscillation and power supply ripple. The ic is very easy to build and you don't have to attach heatsink for normal operation. 2.5 watts power is enough to drive small 8 ohms loudspeaker for your little amplifier project. This wiring diagram is very stable and low oscillate noise even your hand near volume control.

The cost of lm380n around 1$
R1 is 2 kilo-ohms resistor (See how to read resistor color code here)

Beware!!!! Capacitor C1,C3,C4,C5 is electrolytic capacitor so you must check polarity or the capacitor especially C3 will explode,that may cause severe injured,so you must know what you do.

See this ic sound test video.



  2. OK the list is for one channel.
    1 10 kohms potentiometer
    2 C1 2.2uf/25 volts
    3 C2 0.001 uf 100 volts
    4 C3 4700uf/35 volts(16 volts is fine)
    5 C4 1000 uf/25 volts(16 volts is fine)
    6 C5 100 uf/25 volts(16 volts is fine)
    7 LM380n ic
    8 R1 2 kohms 1/4 watts
    9 4 ohms speaker not less than 5 watts if you want play loud music.

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