Electronic Parts & Circuits Explained

The circuit consists of 3 components, Resistor, Capacitor & transistor, before going to circuit let me explain the working of these components (Just basic Idea, I don't Know any deeper). 

 

Resistor
Decrease the flow of current, or convert excess electrical energy to heat energy, some electrical components like transistor, chip need specific voltages as manufacturer says over current or voltage damage the device quickly.

 

Electrolytic Capacitor
Stores Electrical energy. It has 2 leads positive and negative leads, inside both of the leads has massive conducting plates, and in between there is a non-conductive plate. Even a 100uf capacitor has 2 meter long electric plates. When we connect the capacitor to a DC source, ie Flow of electrons in one direction, either P to N or N to P, so all the P charged electrons fill on P plate and N charged electrons on N plate, in case of electrons, magnetism & waves, LIKE one's REPEL & UNLIKE one's ATTRACT here P charge and N charge attracts each other, they cannot discharge/cancel bcoz of non-conducting plate. Even if we disconnect the DC source, electrons stays there because of that positive-negative electron's attraction. In charged time capacitor act as conductors, both the plates are filled with electrons help flow of electricity. The surface area of plate material inside capacitor determines the storage capacity. When discharge happen all electrons in P, N plates find a low resistance path and cancels each other.

Transistor       
Act as a Switch, Regulator, Amplifier. It has 3 leads, Emitter, Collector & Base. On a General purpose transistor there is 2 conducting layer and in between there is a semiconductor layer. As said above P electrons like N electrons & Flow of electron is in 1 direction, When electrons flow it cannot get to other side because of middle Semiconductor layer, it cannot full fill the flow, The semiconductors are designed with impurities , to cover up that impurities we have to provide additional electrons to that layer, When that happen that layer become conductor and allow to flow electrons. that's the basic idea.

Transistor as Switch
All transistors are basically switch, control flow rate or stop current. What make Transistor differ from switch?, It's Speed and accuracy, A transistor can ON and OFF the flow of electron 300 million times a second, on a normal switch only 3 times. The high speed switching is also Known as Oscillator, We come to that later.In transistor there is two types NPN and PNP, Both are same function.

NPN
1) Collector needs positive charge, device to be controlled connected here.
2) Emitter need negative charge
3) Base need small positive charge, the value of this determine flow of electrons from E to C

PNP
1) C needs negative charge, device to be controlled connected here
2) E need positive charge
3) B need small negative charge the value of this determine flow of electrons from E to C

Transistors as Regulators
Voltage Regulators and very much important in an electric circuit, According to fixed base voltage only allowed amount electron is flow through base. This Keeps Voltage Intact. Usage of zener diode also increase the stabilty. A Zener diode will keep the transistor's base voltage steady. In the picture above...
I have 12V from mains eliminator, it'll surely fluctuate according to mains voltage availability (ie 200~300V) ,But I Required clean 6 VOLT without fluctuations, I am using 1 amp rated transistor, 6V rated zenor diode, & a series resistance of 100 ohms. The current flow through R1 and reach at the base of Transistor, Here 6 VOLT Zener Diode, Block exactly 6VOLT and conduct rest, the resistor with 100 ohms resist the flow might be heat up quickly, use 1 watt resistor instead. That Blocked 6 VOLT flow through Base and finish the circuit. Wheather it is 7, 9, 10, 14 any voltages the zener diode only block rated voltage,  rest will pass through it. Here the rest voltages hit the negative through resistance and normalize, and my circuit get Steady Voltage. Adding a capacitor parellel to zener diode make actions smoother.

Transistors as Amplifiers
 As said above switches and regulators keep base voltage intact to preserve output voltage, On a regulator if we provide low base voltage output become low voltage. And if an High base voltage then High output voltage. Amplifier are those devices used to Boost the base voltage or current artificially. Inside an amplifier, Its a big scale copy machine, The incoming Low level source voltage is (Analogue ie High & Low) is normalize with coupling capacitors and base-collector resistors, then the high & low get more gain, sharpness, punch etc and we can control the gain by adjusting Base Collector resistor, this is fed to the base of transistor, and electron'll flow from collector to emitter according to variation of in low level signal+base collector resistor voltage on BASE.

Transistors as Oscillators.
Oscillator aka Multivibrator , need no start up pulse & run forever. Switching of transistors in KHz or MHz are known as oscillators. In an oscillator the oscillations in output ie HIGH and LOW timing is set by a resistor and a capacitor, the capacitor charge and discharge through the resistor and the transistor change the state according to its base voltage from cap.

In a computer everything is start from internal system clock, It is an astable multivibrator oscillator , Every procedure inside a Inverter, computer, LCD TV & mobile phone is based on astable multivibrator.

Simple Homemade Aquarium Pump Ideas

In the case of pumps VALVE is the main component. If you  manage to create a good valve then the pump is ready. Here i am going to construct a simple water pump, with a pen, refil, a resistor, plastic pipe or wire outer covering (Ethernet cable/cable-tv cable is perfect), any flat bottle, connecting sticks and a DC motor

From the above image itself it is clear about the valve concept, this is the basic valve design and all pumps especially PISTON & Diaphragm pump need 2 Valves to work properly , a small pen refil tube inserted inside bigger refil tube, and put a resister inside of it, the small refil keep resistor from falling down. When motor suck the fluid rush in, the suction and water pressure pull resistor up & fluid pass through valve. When motor release the gravity and downward water pressure push resistor down and block the passage.

Here i am gonna explain 2 types of pumps Diaphragm and Piston, 

Diaphragm Pump (left side) 
A small diaphragm pump uses the DC motor to create pulsing hydraulic pressure means no need of excess force a small force is enough to drive the pump. Here We use a circular piece of rubber sheet as Diaphragm (bicycle tube is good, 3 inch diameter is enough for this mini pump, take a flat bottle, cut a hole with 2 inch diameter, and place this rubber sheet in the middle glue all other parts, on the middle of sheet

 During the upstroke , the rubber sheet is pulled up, creating a partial vacuum within the bottle. The vacuum pulls the Input, resistor valve open and the Output, resistor valve is pushed closed by the gravity and fluid pressure in the hose. Water is then drawn into the bottle. On the down-stroke , the input valve is closed and the output valve is forced open as water is discharged to the output pipe. Diaphragm pumps have a relatively small displacement volume. The pump must run fast, even a small or vibratory effect on rubber sheet draws water into chamber easily. Because of less mechanical moving parts, it is easy to construct & Good pressure control. Best for aquarium bubble machine.

Piston Pump (Right side)
Piston pumps used everywhere, toy water-gun, water atomizer, paint sprayer etc, in this pump the pressure is intact. Unlike Rubber sheet more power is needed to move piston up & down rest is same as Diaphragm Pump 

This is a Hose Pump, as the name itself Hose pump need only a flexible pipe to work, these pump don't need any valves, easy to construct, The disadvantages compared to piston & diaphragm pump, is this pump displace only a small amount of fluid through it. But the pressure is intact. To Build a Hose Pump you need a flexible pipe ( i used thin polythene plastic tube, 2cm diameter) attach 2 straw on both ends of flexible pipe. Cut a rectangular piece of thermocole, smooth its edges round. now place thermocole piece on a DC motor and put the flexible pipe around it, in a tight manner, ie wherever the thermocole touches the pipe that area condense and rest expand, this create a vaccum. This Low pressure pull water in, then rotation of thermocole move water outside. Put some oil on thermocole to decrease friction, hence it cause breakage of plastic tube. This pump has less mechanical part, and no valve. 

All parts can be get from home, except DC motor. So try some, post some comments.

Long Range FM Voice Transmitter & Receiver

The range of this FM transmitter is around 500 meters at 3V DC supply and receiver is able to capture signals from 70~100 meters. The circuit consists 3 stages. The first stage is a MIC preamplifier built around BC548 transistor by varying 2K2 with higher values increase the sensitivity of mic. The next stage is the heart of this device an astable multivibrator changes output high and low, at VHF Frequency, Here we use BC548 General purpose NPN transistor,  capable of handling 250mW of current & Oscillates upto 300Mhz This VHF oscillator is fixed to oscillates in the middle of FM band, ie 100MHz with the help of 10pF capacitor and 2K2 and 4turns coil. The preamplified audio from 1st stage is coupled to VHF oscillator with the help of 0.1uf or 104capacitor, The audio signal vary the oscillator frequency and the new frequency ie. audio freq+oscillator freq (signals cancel each other or add up here, ie 100MHz vary from 99.001 to 101.001) is fed to the 3rd stage. This mixed signal is normalized with the help of 10K and 470Pf capacitors attached to +ve and -ve rails respectively. The 3rd part of the circuit is a class-A tuned amplifier that consists of 10pf capacitor & 10 turns coil  boosts signals from the oscillator. Use of the additional RF amplifier increases the range of the transmitter. This part is optional if you want a simple voice transmitter, If you need High Power Transmission you must use high rated transistors with, BC series can hadle upto 250mW of power, ie enough for 200 meter communication.

Now the receiver part is also same as transmitter, first
When electricity pass through a conductor it produces electromagnetic waves around it, if the electricity/frequency is high then it'll propagate to long distance, similarly when electromagenetic waves hit conductor it'll produce electricity, that is very time difficult to measure with any instrument.
From AIR the antenna pick up whatever electromagnetic waves hitting the wire, that mixed signal fed to the 1st part BC548 Oscillator , here also oscillator is oscillating at 100Mhz the incoming mixed signal vary the oscillator frequency or cancel each other and produces required signals. That is Detection, only a allowed part of signal pass rest cancel each other. that output is very low cannot hear, that why we implement a 2nd part preamplifier, that'll convert low level signal to identifiable high and low signals for our amplifier.

 

The output from free preamp is pretty pure, can be fed into our LM386 general purpose amplifier that'll convert it audible sound for a speaker. The sensitivity of the receiver is poor according to the conditions. The receiver cannot be used to receive local FM stations, if you attach the antenna wire to home TV antenna/Dish or Analog Cable plug-point you may get some channels. Here is the Best All purpose amplifier LM386

The Transmitter & Receiver are very simple to understand. The core of both TX & RX is astable multivibrator that oscillates at 100MHz, At TX section the incoming audio signal vary the oscillator signal,At RX section mixed signal fed up with oscillator and cancel the oscillator frequency the final result is usefull signal.