How to de soldering with desoldering wick

How to soldering piezo sensor

Piezo electric Sensor

Transformerless power supply

Over heat indicator

LM35 are precision integrated circuit senser,whose output voltage is linearly proportional to celsius(centigrade) it provides an output of 10mV/Degree celsius.It has a low cost,low output impedence,linear output.It draws a very small current,of the order,of 70uA from its supply and therefore its self heating is small.

The following circuit is a over heat indicator using LM35.The L.E.D is used to get a direct indication of the temperature level sensed by the LM35.

If the temperature crosses the preset value,the base-emitter voltage of the transister exceeds the limit and transistor starts conducting.The L.E.D gradually begins to illuminate.

Caution must be maintained,not exceed the temperature over 150 degree celsius other wise the sensers may get damaged.

MQ 5 gas senser

This type of gas sensers (MQ 5) can detect L.P.G and Natural gas (Not Smoke,Alcohol, Carbon Monoxide,Ammonia, Sulfide and other harmful gases).It is low cost and suitable for different application.The higher concentration of the gas, the output voltage also higher.Sensitivity can also be regulated by preset.MQ 5 sensers is rated to draw less than 900mW@5V. for sensers heating module.

#CHARACTERIZATION :-
1.High sensitivity to combustible gas (300ppm to 3000ppm)
2.Very fast response<10s and resume.
3.Simple circuit,low cost and long life.
4.Heater voltage 5V.

5.Load resistance is adjustable.
6.Sensing resistance 2K Ohm to 20K Ohm(in 2000ppm)
7.Heater consumption 900mW@5V.

RUNNING LED LIGHT

The running LED light generally can not adjust the speed of light.This circuit can adjust the speed of light as needed.Make this circuit can used more versatile.Operation of the circuit is divided into two parts

1.Frequency genarator.

2.Display.

The circuit uses a 555 timer and a 5stage johnson counter (CD4017) having 10 decade output.That outputs (Pin 2,3,4,7,10etc)becomes high and low when the input pin (Pin14) receives pulses from generator IC(555).

Pin 9 is connected to the Pin 15 (Reset Pin) to stop counting.So that the cycle repeats.VR 1 adjust the speed of light.Try it at home and give me a comment ....