Datasheet Reference.com

Project: Using the NE555 in a Magnetically Operated Gun

The circuit is designed to produce a gun using the technology of magnet to drive a minimal hit a long distance horizontally or a few distance vertically. A magnet is an element that creates magnetic field which is a force that pulls on ferromagnetic materials and attracts or repel other magnets. It is created by moving charges such as electric current. It can also be created by the spin magnetic dipole moment, and by the orbital magnetic dipole moment of an electron within an atom.

Circuit Explanation

The operation of the circuit starts with the 555 timer acting as oscillator being operated in astable mode where it performs pulse generation at a rate of 10 ms to the IC2 (4017B). The pin 15 will continue to take low at the fire button, while 4017B keeps on resetting. The outputs of Q1 to Q7 are sequenced by IC2 to provide power to TR1 to TR4 transistors. This in turn will launch in rapid sequence the inductors L1 to L4. The transformer can produce a 25.5 V DC to the electromagnets when rectified and leveled. The winding of the electromagnets on the copper tube will be cut in two after 500 turns. To slide one on the copper tube, the winding should be at the base of reversed sellotape. The physical size of the galvanized wire bullet is 2 mm diameter and 3 cm long. It should freely glide inside the copper tube.

Caution should be observed in positioning the electromagnets L1 to L4 on the copper tube to obtain optimum effectiveness on the movement of the bullet and arranging the voltage across resistor R1.

There are two basic types of electromagnetic gun, the rail gun and the coil gun. Both used stored energy to produce large magnetic field and high electric current through a driving armature. The interaction of the current with the magnetic field generates a force which propels the armature and any projectile connected to it.

Source:www.zen22142.zen.co.uk/Circuits/Misc/maggun.htm

Project: 100 Watt Inverter Circuit with the 2N3055

Description

Here is a 100 Watt inverter circuit using minimum number of components.I think it is quite difficult to make a decent one like this with further less components.Here we use CD 4047 IC from Texas Instruments for generating the 100 Hz pulses and four 2N3055 transistors for driving the load.

The IC1 Cd4047 wired as an astable multivibrator produces two 180 degree out of phase 100 Hz pulse trains.These pulse trains are are preamplifes by the two TIP122 transistors.The out puts of the TIP 122 transistors are amplified by four 2N 3055 transistors (two transistors for each half cycle) to drive the inverter transformer.The 220V AC will be available at the secondary of the transformer.Nothing complex just the elementary inverter principle and the circuit works great for small loads like a few bulbs or fans.If you need just a low cost inverter in the region of 100 W,then this is the best.

Circuit Diagram with Parts List.

Notes.

• A 12 V car battery can be used as the 12V source.
• Use the POT R1 to set the output frequency to50Hz.
• For the transformer get a 9-0-9 V , 10A step down transformer.But here the 9-0-9 V winding will be the primary and 220V winding will be the secondary.
• If you could not get a 10A rated transformer , don’t worry a 5A one will be just enough. But the allowed out put power will be reduced to 60W.
• Use a 10 A fuse in series with the battery as shown in circuit.
• Mount the IC on an IC holder.
• Remember,this circuit is nothing when compared to advanced PWM inverters.This is a low cost circuit meant for low scale applications.

Design Tips.

The maximum allowed output power of an inverter depends on two factors.The maximum current rating of the transformer primary and the current rating of the driving transistors.

For example ,to get a 100 Watt output using 12 V car battery the primary current will be ~8A ,(100/12) because P=VxI.So the primary of transformer must be rated above 8A.

Source: Circuits Today

Also here ,each final driver transistors must be rated above 4A. Here two will be conducting parallel in each half cycle, so I=8/2 = 4A .

These are only rough calculations and enough for this circuit.

Automatic LED Emergency Light

Description

This is the circuit diagram of a low cost emergency light based on white LED.The white LED provide very bright light which turns on when the mains supply is not there.The circuit has an automatic charger which stops charging when the battery is fully charged.

The IC LM 317 produces a regulated 7 V for the charging of Battery.Transistor BD 140 drives the out put.Transistor BC 548 and Zener diode controls the charging of the battery.

Tips

It is always better to connect a heat sink with BD 140.Before using the circuit out put of LM317 must be set to 7V by adjusting the potentiometer. Original article: http://www.circuitstoday.com/automatic-led-emergency-light

Project: Battery Charger Circuit using LM317

Here is a simple but effective battery charger circuit using IC LM 317. The circuit can be used to charge 12V lead acid batteries.The circuit is very simple and can be easily assembled on a general purpose PCB.

The heart of the circuit is IC LM317, which is an adjustable voltage regulator IC.The pin 1 of the IC is the control pin which is used to control the charging voltage.The pin 2 is the output pin at which the charging voltage appears.The pin 3 is the input pin to which the regulated DC supply is given.

The charging voltage and current is controlled by the Transistor Q1, resistor R1 and POT R5.  When the battery is first connected to the charging terminals, the current through R1 increases.This in turn increases the current and voltage from LM317. When the battery is fully charged the charger reduces the charging current and the battery will be charged in the trickle charging mode.  Source: CircuitsToday.

• The input voltage to the circuit must be at least 3V higher than the expected output voltage.  LM 317 dissipates around 3V during its operation.  Here I used 18V DC as the input.
• The charging voltage can be set by using the POT R5.
• The LM 317 must be mounted on a heat sink.
• All capacitors must be rated at least 25V.
• You can use crocodile clips for connecting the battery to the charger.

Control AC Outlets Over a Network with AVR ATmega16

Synopsis: Using an Atmel NGW100, Olimex AVR I/O relay board, and some electrical elbow grease, I made a network accessible AC Outlet Control.

The purpose of this project was to see what it would take to build a remote controlled outlet. The basic requirements were that I wanted to be able to use a secure shell to log in to a device and tell it to turn on or off a 120V A/C socket.

Using a $69 Linux embedded board (an Atmel NGW100), an AVR microcontroller relay board, open source development tools (WinAVR), and some home-brewed software and electrical elbow grease, I now have a system I can use to hard boot a server remotely.    Read the details at: http://sawdust.see-do.org/power/files/AVRRemoteACControl.html

Desktop Line Following Robot with AVR ATmega16 Microcontroller

The line follower is one of the self operating robot that follows a line that drawn on the floor. The basic operations of the line following are as follows:
 

1. Capture line position with optical sensors mounted at front end of the robot. Most are using several number of photo-reflectors, and some leading contestants are using an image sensor for image processing. The line sensing procss requires high resolution and high robustness.
2. Steer robot to track the line with any steering mechanism. This is just a servo operation, any phase compensation will be required to stabilize tracking motion by applying digital PID filter or any other servo argolithm.
3. Control speed according to the lane condition. Running speed is limited during passing a curve due to friction of the tire and the floor.

There are two line styles, white line on the black floor and black line on the white floor. Most contest are adopting the first one in line width of between 15 and 25 millimeters.  Read the details here: http://elm-chan.org/works/ltc/report.html

Project: FM Transmitter with the 2N2222

Here is the schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used as a room or telephone bug.

Project: How to Make a Temperature Recorder using LM35

Here is how you can make an LM35 an temperature recorder by using the 12F675 PIC microcontroller as the controller and data store. It generates serial output so that you can view the results on a PC and it also calculates the temperature reading in Fahrenheit sending both to the serial port at half second intervals. See it Step by Step.

Project: How to Waterproof a LM35 Temperature Sensor

Here is a instructable to waterproof a LM35 for use on a tethered ROV using a automobile 12V battery as a power source. This came out of a need for the MATE ROV Competition. The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.  See it Step by Step.

LM317 Application Notes: LED Constant Current Source Scheme

(Excerpt) The LM317L wants to see 1.25 V between its VOUT pin and the Vadj pin, and it will do whatever it can to keep that voltage differential between them.

But what if a series/parallel combination of LEDs is wanted in the LM317 circuit? The following circuit works fine, assuming that there are not large variations in the forward voltage drop of the LEDs. There could be a problem however if one of the strings opens up for some reason. The LEDs that remain would have 50% more current flowing through them, which could cause them to be driven too hard and fail. So how does one get around this problem? Download LM317 Application Note from On Semi.

Project: LM317 Variable Power Supply

A truly timeless circuit. LM317 is a versatile and highly efficient 1.2-37V voltage regulator that can provide up to 1.5A of current with a large heat sink. It's ideal for just about any application. This was my first workbench power supply and I still use it. Since LM317 is protected against short-circuit, no fuse is necessary. Thanks to automatic thermal shutdown, it will turn off if heating excessively. All in all, a very powerful (and affordable!) package, indeed. Although LM317 is capable of delivering up to 37V, the circuit pictured here is limited to 25V for the sake of safety and simplicity. Any higher output voltage would require additional components and a larger heat sink. Make sure that the input voltage is at least a couple of Volts higher than the desired output. It's ok to use a trimmer if you're building a fixed-voltage supply.

Output voltage is set by two resistors R1 and R2 connected as shown below. The voltage across R1 is a constant 1.25 volts and the adjustment terminal current is less than 100uA. The output voltage can be closely approximated from Vout=1.25 * (1+(R2/R1)) which ignores the adjustment terminal current ``but will be close if the current through R1 and R2 is many times greater. A minimum load of about 10mA is required, so the value for R1 can be selected to drop 1.25 volts at 10mA or 120 ohms. Something less than 120 ohms can be used to insure the minimum current is greater than 10mA. The example below shows a LM317 used as 13.6 volt regulator. The 988 ohm resistor for R2 can be obtained with a standard 910 and 75 ohm in series.

When power is shut off to the regulator the output voltage should fall faster than the input. In case it doesn't, a diode can be connected across the input/output terminals to protect the regulator from possible reverse voltages. A 1uF tantalum or 25uF electrolytic capacitor across the output improves transient response and a small 0.1uF tantalum capacitor is recommended across the input if the regulator is located an appreciable distance from the power supply filter. The power transformer should be large enough so that the regulator input voltage remains 3 volts above the output at full load, or 16.6 volts for a 13.6 volt output.

LM317T Voltage Regulator with Pass Transistor

The LM317T output current can be increased by using an additional power transistor to share a portion of the total current. The amount of current sharing is established with a resistor placed in series with the 317 input and a resistor placed in series with the emitter of the pass transistor. In the figure below, the pass transistor will start conducting when the LM317 current reaches about 1 amp, due to the voltage drop across the 0.7 ohm resistor. Current limiting occurs at about 2 amps for the LM317 which will drop about 1.4 volts across the 0.7 ohm resistor and produce a 700 millivolt drop across the 0.3 ohm emitter resistor. Thus the total current is limited to about 2+ (.7/.3) = 4.3 amps. The input voltage will need to be about 5.5 volts greater than the output at full load and heat dissipation at full load would be about 23 watts, so a fairly large heat sink may be needed for both the regulator and pass transistor. The filter capacitor size can be approximated from C=IT/E where I is the current, T is the half cycle time (8.33 mS at 60 Hertz), and E is the fall in voltage that will occur during one half cycle. To keep the ripple voltage below 1 volt at 4.3 amps, a 36,000 uF or greater filter capacitor is needed. The power transformer should be large enough so that the peak input voltage to the regulator remains 5.5 volts above the output at full load, or 17.5 volts for a 12 volt output. This allows for a 3 volt drop across the regulator, plus a 1.5 volt drop across the series resistor (0.7 ohm), and 1 volt of ripple produced by the filter capacitor. A larger filter capacitor will reduce the input requirements, but not much.

LM35 Sensor Background and Applications

Most commonly-used electrical temperature sensors are difficult to apply. For example, thermocouples have low output levels and require cold junction compensation. Thermistors are nonlinear. In addition, the outputs of these sensors are not linearly proportional to any temperature scale. Early monolithic sensors, such as the LM3911, LM134 and LM135, overcame many of these difficulties, but their outputs are related to the Kelvin temperature scale rather than the more popular Celsius and Fahrenheit scales. Fortunately, in 1983 two I.C.’s, the LM34 Precision Fahrenheit Temperature Sensor and the LM35 Precision Celsius Temperature Sensor, were introduced. This application note will discuss the LM34, but with the proper scaling factors can easily be adapted to the LM35.

The LM35/LM34 has an output of 10 mV/°F with a typical nonlinearity of only ±0.35°F over a −50 to +300°F temperature range, and is accurate to within ±0.4°F typically at room temperature (77°F). The LM34’s low output impedance and linear output characteristic make interfacing with readout or control circuitry easy. An inherent strength of the LM34 sensor over other currently available temperature sensors is that it is not as susceptible to large errors in its output from low level leakage currents. For instance, many monolithic temperature sensors have an output of only 1 μA/°K. This leads to a 1°K error for only 1 μ-Ampere of leakage current. On the other hand, the LM34 sensor may be operated as a current mode device providing 20 μA/°F of output current. The same 1 μA of leakage current will cause an error in the LM34’s output of only 0.05°F (or 0.03°K after scaling).

Low cost and high accuracy are maintained by performing trimming and calibration procedures at the wafer level. The device may be operated with either single or dual supplies. With less than 70 μA of current drain, the LM34 sensor has very little self-heating (less than 0.2°F in still air), and comes in a TO-46 metal can package, a SO-8 small outline package and a TO-92 plastic package.

The LM35/LM34 is a versatile device which may be used for a wide variety of applications, including oven controllers and remote temperature sensing. The device is easy to use (there are only three terminals) and will be within 0.02°F of a surface to which it is either glued or cemented. The TO-46 package allows the user to solder the sensor to a metal surface, but in doing so, the GND pin will be at the same potential as that metal. For applications where a steady reading is desired despite small changes in temperature, the user can solder the TO-46 package to a thermal mass. Conversely, the thermal time constant may be decreased to speed up response time by soldering the sensor to a small heat fin.

Project: LM3886 Based 300W Audio Power Amplifier

Full audio power amplifier project based on six LM3886 high performance ICs providing 300 watts of power into 4 Ohm speakers.  Futher information on the LM3886 Amp Project is here.

Project: 2N2222 FM Transmitter

This circuit is a simple two transistor (2N2222) FM transmitter. No license is required for this transmitter according to FCC regulations regarding wireless microphones. If powered by a 9 volt battery and used with an antenna no longer than 12 inches, the transmitter will be within the FCC limits. The microphone is amplified by Q1. Q2, C5, and L1 form an oscillator that operates in the 80 to 130 MHz range. The oscillator is voltage controlled, so it is modulated by the audio signal that is applied to the base of Q2. R6 limits the input to the RF section, and it's value can be adjusted as necessary to limit the volume of the input. L1 and C6 can be made with wire and a pencil. The inductor (L1) is made by winding two pieces of 24 gauge insulated wire, laid side by side, around a pencil six times. Remove the coil you have formed and unscrew the two coils apart from each other. One of these coils (the better looking of the two) will be used in the tank circuit, and the other can be used in the next one you build. The antenna (24 gauge wire) should be soldered to the coil you made, about 2 turns up from the bottom, on the transistor side, and should be 8-12 inches long. To make C6, take a 4 inch piece of 24 gauge insulated wire, bend it over double and, beginning 1/2" from the open end, twist the wire as if you were forming a rope. When you have about 1" of twisted wire, stop and cut the looped end off, leaving about 1/2" of twisted wire (this forms the capacitor) and 1/2" of untwisted wire for leads.

Project: Economic Battery Sufficiency Tester with BC547 Circuit

Battery level indicators generally detect the voltage levels of the batteries to give a result. So, tester circuits must not be a heavy load during the measurement process. This tester circuit draws very low current. A short duration of LED bright will show you the battery has still enough voltage level to operate devices. This light brights due to the discharging of C1 on D1 LED, this happens only when the battery provides enough voltage. When you close the S1 switch, Tr1 transistor makes C1 to discharge through R3 current limiter. Minimum required battery voltage level can be determined by using voltage divider R1/R2. Values of R2 and R3 must be calculated as shown below;

R2 = (0.6 x R1) / (Vbmin - 0.6) Ohm and R3 = (Vb - 1.4) / 0.2 ohm

For example, for 6.5Vb(min) value (to test a 9V battery) R2 must be 10k and R3 must be 39 ohm. R4 must be between 10k and 1M. For higher values of R4, circuit becomes more economed after abic but this causes lenghten the test period. When R4 is 100k, battery can be testout 10 seconds.

 Transistor

Project: Gaincard Like Amplifier

LM3886 2×68 Watt Amplifier Full Project description. In this application, we are building a gaincard like amplifier. This application type is named gainclone in audio world. To take a satisfactory audio response, we are adding a Linkwitz equaliser to the feedback line and adding bass compensation also. We are using LM3886 which is the revised version of its brother LM3875.  Full instuctions and circuit schematics, PCB board layout are here.

Project: Guitar Power Amp

This is a powerful amplifier based on the LM3886 or LM3876 IC. This little amp is capable of some massive sounds at up to 68 watts. You'll need 18 dc volt bipolar power.  Here's the spec. Source General Guitar Gadgets.

Project: Headlights Timer with a BC547 Transistor

Pushing on P1 allows C1 charging to full 12V battery supply. Therefore Q1 is driven hard-on, driving in turn Q2 and its Relay load. The headlights are thus activated by means of the Relay contact wired in parallel to the vehicle headlight switch. RL1 remains activated until C1 is almost fully discharged, i.e. when its voltage falls below about 0.7V. The timing delay of the circuit depends by C1 and R1 values and was set to about 1min. and 30sec. In practice, due to electrolytic capacitors wide tolerance value, this delay will vary from about 1min. and 30sec. to 1min. and 50sec. An interesting variation is to use the inside lamp as a command source for the timer. In this way, when the door is opened C1 is charged, but it will start to discharge only when the door will be closed, substituting pushbutton operation. To enable the circuit acting in this way, simply connect the cathode of a 1N4002 diode to R1-C1 junction and the anode to the live lead of the inside lamp. This lead can be singled-out using a voltmeter, as it is the lead where a 12V voltage can be measured in respect to the vehicle frame when the lamp is on.

Project: Ignition Coil Driver with 2N3055 and 555 Timer

Here is a very simple circuit that will provide high voltage (15-40kV) sparks using a common ignition coil. The input is 12VDC at around 5 to 6 amps. Mine produces sparks that are about 3/4" to 1" in length. A 2N3055 NPN power transistor is pulsed with a square wave signal that comes from the 555 timer IC. The frequency of the pulses depends on the resistors between pins 7 and 8 and between pins 7 and 6. The pulse is also dependent on the capacitor. You can experiment with these values. Try inserting a smaller capacitor to raise the frequency. At different frequencies the sparks will change certain characteristics. At a high frequency the sparks will get fatter but shorter in length. At lower frequencies the spark maybe longer but thinner. I assembled my project on a solderless breadboard. You can use whatever you like. The capacitor should be a tantalum or mylar type, but this is not absolutely necessary. A ceramic type should work fine just as long as the temperature is not too high around it. Read more: http://www.geocities.com/CapeCanaveral/Lab/5322/coildrv.htm

Project: Ignition Coil Driver with 2N3055 Transistor and 555 IC

Here is a very simple circuit that will provide high voltage (15-40kV) sparks using a common ignition coil. The input is 12VDC at around 5 to 6 amps. Mine produces sparks that are about 3/4" to 1" in length. A 2N3055 power transistor is pulsed with a square wave signal that comes from the 555 IC Timer. The frequency of the pulses depends on the resistors between pins 7 and 8 and between pins 7 and 6. The pulse is also dependent on the capacitor. You can experiment with these values. Try inserting a smaller capacitor to raise the frequency. At different frequencies the sparks will change certain characteristics. At a high frequency the sparks will get fatter but shorter in length. At lower frequencies the spark maybe longer but thinner. I assembled my project on a solderless breadboard. You can use whatever you like. The capacitor should be a tantalum or mylar type, but this is not absolutely necessary. A ceramic type should work fine just as long as the temperature is not too high around it.  Read more: http://www.geocities.com/CapeCanaveral/Lab/5322/coildrv.htm

Project: Inertial GPS with the AVR ATmega128

This project's goal is to determine the user's position with a commercial GPS system aided by MEMS accelerometers and gyroscopes. The additional MEMS sensors allow for prediction of the user's movement in between and in absence of the absolute GPS updates. Using the ATMEL MEGA128, we combined these sensors to create a compact and easy to use unit!

The primary use of this system would be for in-car GPS where velocities are relatively high (>~1 m/s). Our motive for creating this system is that traditional GPS receivers have problems holding a signal lock when occluded by large buildings in cities. With the inertial reference, GPS outages are not as detrimental to position estimation, as the gyros and accelerometers can be used for pose estimation for many seconds!

Feel free to check out the site to learn more about our implementation, or take a look at our source code to find out what really going on under the hood.  Get the full project details from Cornell University.

LM339 Comparator Project: VU Meter

The circuit uses two lm339 voltage comparators to illuminate a series of 8 LEDs indicating volume level. Each of the 8 comparators is biased at increasing voltages set by the voltage divider so that the lower right LED comes on first when the input is about 400 millivolts or about 22 milliwatts peak in an 8 ohm system. The divider voltages are set so that each LED represents about twice the power level as the one before so the scale extends from 22 milliwatts to about 2.5 watts when all LEDs are lit. The sensitivity can be decreased with the input control to read higher levels. I have not built or tested this circuit, so please let me know if you have problems getting it working. The power levels should be as follows:

• 1 LED = 22mW
• 2 LEDs = 42mW
• 3 LEDs = 90mW
• 4 LEDs = 175mW
• 5 LEDs = 320mW
• 6 LEDs = 650mW
• 7 LEDs = 1.2 Watts
• 8 LEDs = 2.5 watts

Project: Simple 60 Watt Power Amplifier with 2N3055 Transistor

The first version of the amp shown here uses a single power supply and capacitor coupled speaker. It also uses quasi-complementary symmetry for the output stage. Note the really sneaky way the Class-A driver amp's collector load is bootstrapped !

Quasi-complementary symmetry was a scheme used in the days when PNP power transistors were expensive and useless. If you wanted any sort of voltage and current rating, you had to use NPN devices. The quasi-complementary output stage used a (discrete) Darlington for the positive side, and a complementary pair for the negative (i.e. a PNP driver coupled to an NPN power transistor).

Almost all amps of the era from which this circuit originated used the 2N3055 power transistor - this was the pre-eminent power transistor (NPN of course), and there were no vaguely equivalent PNP devices for less than about 5 times the price, and even these were highly inferior. As a result, the quasi-complementary output was very common, until decent PNP power devices became more readily available. Immediately, just about everyone started using NPN and PNP Darlington coupled devices for the output stages (as shown for Q3 and Q4) - the funny part is that it was demonstrated back in the mid 1970's that the full Darlington connection actually sounds (or at least measures) worse than quasi-complementary stages. Read full details:http://sound.westhost.com/project12.htm

Project: Voltage Controlled Switch with a BC547 Transistor

This voltage controlled switch circuit operates when a voltage level which is previously adjusted is applied to the input. Circuit is designed for 24V supply but can be used in a range of 18V-36V. Voltage level which triggers the circuit can be adjusted by P1 potentiometer. A stabilized voltage is applied to this potentiometer through zener diode and Tr5. When the input voltage level exceeds this value TR1 starts conducting and afterwards Tr2, Tr3, Tr4 transistors conduct and relay switches on. Switch S1 that is connected to relay, carries the signal from Tr3 to Tr1 through R1 and keeps Tr1 conducting. When the input is short circuited, D1 diode keeps the circuit operating and you can omit it if you want.

Project: Transistor Shortwave Radio

Designed by Charles Kitchin, N1TEV, the schematic appeared in the August 18, 1994 edition of EDN magazine. The article is titled, “$10 receiver has microvolt sensitivity.”

This radio uses three 2N2222 transistors, while the P-Box radio uses one NPN transistor and two PNP transistors. The 2N2222s are easy to come by.