Transistor Led Flasher

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This circuit has only two transistors, two capacitors and four resistors. That also means it consumes very little power

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You can control the flash rate by changing the size of the 47k resistors. You can also control the duty cycle by using resistors of different values on the two sides. The 330 ohm resistors control the current through the LEDs. Normally you want to limit this to 20mA, but to conserve battery power, you may need to limit it even further. You can also connect several LEDs in series, instead of using only one for each side. With red LEDs (1 per side) and the values shown, the circuit draws about 11mA. 

Part List

c828         = 2

330 Ohm  = 2

47k           = 2

47uF         = 2 

LED          =2

Spy Bug Fm Transmitter

Spy Bug Fm Transmitter

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This fm wireless transmitter should only be used for educational purposes.

Regular transmission using such a transmitter without a licence is illegal.

I would like to tell you not to use this for illegal things

This transmitter can deliver signals up to 50 meters. The transistor 2N2222 serves as the modulator 

as well as oscillator. Capacitor 33pf and inductor L1 forms the necessary tank circuit for making 

oscillation. Adjustments in the transmission frequency can be made by compressing or relaxing

the coil. The voice to be transmitted is coupled to the base of Q1 using an electret microphone. 

The FM signal available at the collector of Q1 is radiated using the antenna.

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Notes.

    Use a 3V battery for powering the circuit.

    The circuit can be assembled on a Vero board.

    Coil L1 can be made by making 5 turns of 24AWG wire on a 1cm plastic former.

    Antenna can be a 25cm long 18AWG wire.

5V Power Supply

5V Power Supply

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A voltage regulator is used to produce a constant linear output voltage. It’s generally used with AC to DC power supply. And also it can be used as well as a DC to DC voltage converter . 

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The LM78XX series typically has the ability to drive current up to 1A. For application requirements up to 150mA, 78LXX can be used. LM7805 has three legs: Input leg which can hold up to 36VDC Common leg (GND) and an output leg with the regulator's voltage. For maximum voltage regulation, adding a capacitor in parallel between the common leg and the output is usually recommended. Typically a 10uF & 100nF capacitor is used. This eliminates any high frequency AC voltage that could otherwise combine with the output voltage. See below circuit diagram which represents a typical use of a voltage regulator. 

Its output voltage is +5V DC that we need. You can supply any voltage in input; the output voltage will be always regulated +5V. But my recommendation is, don’t supply more than 18V or less than 8V in input. There used three capacitors in this voltage regulator circuit, they aren’t mandatory to use. But it will be best if you use them. They helped to produce a smooth regulated voltage at output. Use electrolyte capacitor instead of ceramic capacitor.

One limitation of 7805 I have found that is its output current 1A maximum. Otherwise it is a good voltage regulator if you are happy with 1A. But if   you need over 400mA current in output then you should use a Heat Sink with IC LM7805. Otherwise it may fall damage for overheating.

Part list

LM7805

1000uF

10uF

100nF

LA4440 IC Amplifier

 LA4440 IC Amplifier 

This is the circuit of amplifier using IC LA4440. The amplifier circuit uses very less components but a very high quality with

respect to its cost and ideal for beginners.

IC LA 4440 is wired as a bridge amplifier to deliver a 19 W Rms on a 4 Ohm speaker atau 6 W rms jika di fungsikan stereo.

The IC has built in thermal over voltage and short circuit protection.The IC also incorporates a audio muting function.

Note:

* Use a 12 VDC / 3 A power supply, IC LA4440 can with stand up to 18 volts, but I prefer it should not be nothing more than 16V.

* Do not forget to fit a proper heat sink with IC.

*Use a 4 Ohm speaker

   Click Here to view Datasheet

IC LA4440 Features

Built-in 2 channels enabling use in stereo and bridge amplifier applications. (Stereo 6 Watt Bridge : 19W)

Minimum number of external parts required.

Small pop noise at the time of power supply ON/OFF and

good starting balance.

Good ripple rejection : 46dB (typ.)

Good channel separation.

Small residual noise (Rg=0).

Low distortion over a wide range from low frequencies to high frequencies.

Easy to design radiator fin.

Built-in audio muting function.

Built-in protectors.

Thermal protector

Over voltage, surge voltage protector

Pin-to-pin short protector

Quick Data IC LA4440

Maximum supply voltage.............................18 V.

Allowable power dissipation Pd max............15 W.

Operating temperature Topr........................–20 to +75.

Storage temperature Tstg............................–40 to +150.

Voltage gain VG..........................................49.5 to 53.5.

Output power PO....................................... Stereo 06 W, Bridge 19 W.

Input resistance ri ............................. ....... 30kOhm.

LM386 IC Audio Amplifier

LM386 IC Audio Amplifier

All that is needed to build an audio amp are a few external components. I used sop-8 type ic.

It is well suited to low power applications and runs just fine on a 9 volt battery or 

any voltage supply from 4-12 volts. 

It has a low quiescent current drain of only 4mA so it won’t kill a battery right away

if you leave it on and idle. The gain is internally set to 20 but the addition of an

external resistor and capacitor between pins 1 and 8 will increase the gain to any

value from 20 to 200. An increase in bass frequency can be facilitated by adding a

10K resistor and .033 uf capacitor in series between pins 1 and 5.

   Click Here to view Datasheet

Parts List

LM368 

100uF

220uF

10uF

0.047uF (473)

0.01uF (103)

10 ohm

10k V/R

4026 IC 7 Segment Counter

4026 IC  7 Segment Counter 

This circuit diagram is a simple digital revolution counter. It can be used to count the rotation of a machine 

like coil winding machine etc.  

Mechanical part

It has two sections. One is the mechanical which converts the shaft rotation into clock pulses. Other one is an counter.

The details of the mechanical parts are shown in figure(2). 

(1)  Make mechanical part as showen in the figure(2)

(2)  take a DVD or CD and put a drill hole (1cm diameter.) at outer periphery as shown in figure(2).

(3)  Fix the disc in the shaft and enclose the whole things showen in the figure(2).

(4)  Fix one white LED and a Photo diode (LDR) face to face on each side 

       Now the mechanical part is ready

   Click Here to view Datasheet

Parts List

* CD 4026 ic                               = 4

* 7 Segment Display (common cathode ) = 4

* Photo diode (LDR)                        =1

* white LED                                   =1

* C828 Transistor                      =1

* 2K                               =  1

* 50K V/R                = 1

* 10K                     = 1

* 2K2             =1

* 9V Relay   =1

FM transmitter 800m (2400ft)

FM transmitter 800m (2400ft) 

This fm wireless transmitter should only be used for educational purposes.

Regular transmission using such a transmitter without a licence is illegal in most countries.

I would like to tell you not to use this for illegal things

This is one of the smallest and neatest FM transmitters to be presented as a construction project

This will save going to a number of suppliers as no single supplier has all the 

necessary components. 

FM transmission is the best mode for transmitting a signal as it does not suffer 

from interference such as electrical noise from car engines or electrical appliances

etc. It also achieves the greatest range with the least power.

With just a handful of components and a few milliwatts of output power you can 

produce an FM transmitter with a very impressive range and perfect clarity.

With a 175cm (5ft 9in) (half-wave antenna) the range has been 

conservatively rated as 800 meters (2400ft) under normal working conditions. In many 

countries you must reduce the maximum range to 30ft (10 meters) by cutting the antenna

to 10 inches. If this is the case, you must abide by it. Some countries totally ban

these brilliant devices. You need to find out the situation in your own locality.

Using a battery for powering the circuit will reduce noise. 

For More Details Visit 

http://www.talkingelectronics.com/projects/Voyager/Voyager-P1.html

PARTS LIST

SEMICONDUCTORS

2 - 2N2222   (NPN transistors)      Click Here to view Datasheet

RESISTORS

1 - 470R  

1 - 10k    

1 - 47k   

1 - 68k   

1 - 1M    

CAPACITORS

1 - 10p ceramic-disc 

1 - 39p ceramic-disc 

1 - 1n ceramic-disc 

2 - 22n ceramic-disc

1 - 100n 

1 - 5p to 30p air trimmer

ADDITIONAL PARTS AND MATERIALS

1 - 5 turn coil 0.020inch (0.5mm) enamelled wire 1/8in (3mm) diameter

1 - electric microphone

1 - 9v battery 

1 - 9v battery snap

12in (30cm) fine solder

5ft 9in (175cm) hook-up wire.

SUMMARY OF SPECIFICATIONS

Supply:- 9 volts
Current consumption:- 7mA
Tuning range:- 80 - 110MHz (by stretching or compression the oscillator coil)
Fine tune by adjusting the air trimmer (2MHz adjustment)
Stability:- Low. Bug to be left in-place and not to be moved or handled.
Antenna length - 175cm (5ft 9in)