Category Archives: Electronic Circuit

DIY – USB Mini Fan

This is a very easy guide to make an usb powered mini fan.


– 1 usb cable
– 1 quadcopter propeller
– 1 breadboard
– soldering iron + tin
– 2 jumper wire
– 1-3 0,1 microfarad 50v capacitor
– 1 usb charger (alternatively you can powered up the fan later using power bank or usb port from pc or laptop or any usb charger)



First of all, cut the usb cable and isolate the plus and minus from the data transfer cables (green and white is data transfer cable).


As we already know that any usb cable consist of 4 different cables:

The red one is for positive volt, the black one is for negative volt, the green will be used for upstream data transfer and the white one will be used for downstream data transfer.

Here we got isolated plus and minus cable where each of the cable has been soldered with tip of jumper wire (the red and black one) which is ready to be plugged into our positive and negative spot on breadboard.


Next solder the 0.1 µF ceramic capacitor across the motor dc (we can use 1-3 capacitor to deal with motor noise), and plug the quadcopter propeller on top.

Once the ceramic capacitor has been soldered, add 2 jumper wires in order to plug it to breadboard.


And finaly, plug the usb cable and the jumper wire from motor dc on the breadboard and the usb fan is ready.


This usb fan is ready to powered via any 5v power supply. You can powered it with a charger, any usb port from laptop or pc, any power banks or any other 5v power supply.

Here’s the usb fan in action:


Switch Based on Contact (SPST, SPDT, DPST, DPDT)

by : Antonius (@sw0rdm4n)

Understanding switch types is very important when developing an electronic circuit. Below is just several example of switches (not a complete list) classified by pole(s) and throw(s).



SPST stands for single pole single throw.  Pole means how many circuit(s), a switch can control. Throw means how many conducting position for a switch. This one is the basic form of a switch, where this switch has only 2 terminals. When the throw is closed means current can flow, meanwhile when the throw is open, current is break.

In order to understand more, let’s take a look here (sorry for bad drawing skills)



For example here we have a gate when the gate is open, means the electrical flow is break.


When the gate is closed means current can flow and the lamp is on. Since this only has 1 circuit (the lamp in this case), and only 1 throw (only 1 conducting position that will turn the light on, so this switch is called SPST).

Real life example:




SPDT stands for single pole double throw. As we can see from the symbol, a single pole double throw switch has 3 terminals.

In order to understand more, let’s take look at below example:


This one is similar to knife switch model, where the condition is open (current can not flow). The throw can be connected whether on right or left terminal.



Real life example




DPST stands for double pole single throw.

In order to understand about double pole single throw, take a look on below example.


in dpst , the throw only have one possible conducting, meanwhile it has 2 separate poles.


When the condition is closed the current can flow to light both 2 circuits. The while lines are any conducting materials.



DPDT stands for double pole double throw. This one has 2 poles and 2 throws. This one has 6 terminal(s).

Check out below example:



Real life example:




I hope this guide can be a light for those who wanted to understand more about switching in order to do the “Art of controlling the electron”.



Making an Electronic Torch – Schematic, PCB Version and Breadboard Version

by : Antonius (@sw0rdm4n)

Electronic Torch is an unique electronic circuit to learn about how electric flow through each components. Below is the electronic circuit:


Part Lists Based on Above Schematic

– 2 resistor 330 ohm or 320 ohm. (breadboard version can uses up to 3 resistors)

– 3 led

– 3 switch

– 1 Dioda in4001

How this works on PCB Version ?

Below is the electronic circuit logic flow :

– If switch is on,  the current will flow  through:

D1 (since it’s a dioda it will prevent reverse current) ->  switch ->  R1 -> led1 -> led2 -> ground

– If s1 is on,  the current will flow  through:

D1 -> S1 -> R1 -> led1 -> led2 -> ground.

– if s2 is on, the current will flow through:

D1 -> S2 -> R2 -> led 3 -> ground

Solder each component based on above schematic



– Clean your solder with sponge before soldering

– Before soldering drop some soldering tin on top of your solder

– Don’t use to much soldering tin

And here comes the pcb version of the torch :


Breadboard Version

We can also making breadboard version, vero board version, and so on. Here’s the breadboard version of this electronic torch with 3 resistor (1 resistor 330 ohm and 2 resistor 320 ohm).


To see how this circuit works, you can see this video:

Basic Electric Circuit Laws

By : Antonius (sw0rdm4n)

There are several electric circuit laws, some famous laws are kirchoff’s law and ohm’s law.


Ohm law calculation is the easiest calculation on electric circuits. Ohm law applied in hydraulic mechanism, electric circuits, etc. Ohm’s law on electric circuit defines that the pressure (voltage) is the volume of electricity multiplied with the resistance :

V = I.R

V = volt , volt is the pressure of electricity.

I = ampere, ampere is volume of electricity

R = resistance

I = V/R

as an example we have some little electric circuit :


As an example pressure = 9V, resistance = 220 Ω, So current can be calculated so easily :

I = 9/220

So current is:

I = 0,04 ampere


Kirchoff law defines on the voltage and ampere. Kirchoff’s law on current (volume of electricity):

Σi = 0

As an example here we have simple circuit:


Suppose we will calculate I4 if:

I1 = 0,4 A (positive current)

I2 = 2A (positive current)

I3= 1A (negative current)

This is the simple algebra:

Σi = 0

i1 + i2 = i3 -i4

i1+i2 – i3 -i4 = 0

(0,4 + 2 ) – 1 – i4 = 0

i4 = 2,4 – 1 = 1,4A

Second law is kirchoff pressure law:

Σv = 0

For an example we have a simple electric circuit:



v1 = 20 volt

v2 = 10 volt

R1 = 110 Ω

R2 = 220 Ω

Current (I) calculation is simple :

Since Σv = 0 :

V1 – (I * R1) – V2 – (I * R2) = 0

20 – (I * 110) – 10 – (I * 220) = 0

10 – (I * 110) – (I * 220) = 0

10 =  (I * 110) +  (I * 220)

10 =  i * 330

I = 10/330

I = 0.030

So the current is 0,030 ampere.