### 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…

### How to build high current hall effect sensor

I published hall effect sensor circuit diagram and my audience asked me how to make a hall effect sensor that has a high current capability, so I made it for him and for all of you who want to build high current hall effect sensor.

Normally, hall effect sensor used for detect magnetic field and send output to a microcontroller, that means any hall effect sensor doesn't need to have high current output. However, if you want to drive motor or any high current device without a microcontroller, this circuit is the best for you.

List of components for this project:

1 x IRF 9540N (P channel MOSFET)
1 x A3144 hall effect sensor
1 x 1 kilo-ohms resistor
1 x 10 kilo-ohms resistor
optional (use for led indicator)
1 x 1 kilo-ohms resistor
1 x White, red, blue or any other low current led

Note: all resistor for this circuit is 1/4 watt, 20 % tolerance is ok with this circuit.

The principle of this circuit:

When hall effect sensor detects magnetic field, it sends output low (0 volts) to P channel Mosfet.
P channel Mosfet starts to conduct current when Gate pin has lower voltage potential than Source pin.
Mosfet is a voltage control device so it is easy to drive a Mosfet with low output current sensor like hall effect sensor, light sensor.