555 Timer Circuits
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This simple CPO is for those who want to practice Morse Code in a different way, ie with out the morse key. It can be also used as a touch operated door bell. The popular timer IC555 is wired as astable multivibrator. The frequency (tone) can be changed by.... -
IR appliances use pulses (control signals) sent over a modulated IR carrier wave. The carrier wave may be modulated at various frequencies, 36-38KHz being the most popular.Some Satellite receivers use even higher frequencies than this. The IR1 remote module.... -
A simple two tone water alarm that is light enough to be worn on the upper arm of a sleeper is described. It uses two LMC555 CMOS timer chips followed by a complimentary pair of emitter followers to drive an 8 ohm speaker. Power is supplied by a 9 volt.... -
The 555 timer IC is connected for Astable Operation, the clock pulses are fed to the 4017 IC via the 10K resistor. The 4017 is a 10 stage counter, each of the outputs is connected to the appropriate LED, as some LEDs need to be on for more than one count, we.... -
This circuit detects metal and also magnets. When a magnet is brought close to the 10mH choke, the output frequency changes. .. -
This circuit is built around one of the most popular timer integrated circuits, the 555 timer. It will flash the led on and of at regular intervals. From left to right, the two resistors and the capacitor set the time it takes to turn the led on or off, by.... -
The 555 is configured in the standard astable oscillator circuit designed to give a square wave cycle at a period of around 1 cycle/sec. A potentiometer is included in the design so the period can be set to exactly 1 second by timing the LED flashesc. A.... -
The tool is based on a NE555 (or LM555) timer i.c., wired as an astable multivibrator. The frequency of the multivibrator is determined by the value of the unknown capacitor Cx. The circuit can be fed by a small battery. I use myself a 9 V block battery.... -
Here is the circuit diagram of simple but highly effective TV remote jammer circuit. Most of the TV remotes have 38KHz operating frequency. A flood of IR beams in the same frequency can easily confuse the TV receiver and this is the operating principle of.... -
is circuit was requested from an email. It will allow your car headlights to flash on and off at the same time or it will cause them to flash alternately. The circuit is based on the 555 timer. It is used in the astable mode. The 555 timer output will go.... -
This simple circuit has helped me out on many occasions. It is able to check transistors, in the circuit, down to 40 ohms across the collector-base or base-emitter junctions. It can also check the output power transistors on amplifier circuits. Circuit.... -
I ride my bike allot at night and sometimes I'm not sure if people can see me. This circuit will flash an incandescent light that you can purchase from Radio Shack. Adjust the VR's for your flash requirements and make sure that the lamp you use is designed.... -
This alarm circuit is based on two 555 timers. The alarm will sound your car horn if anyone opens the car door while the circuit is armed. The timers will allow you to leave the car without sounding the horn. To turn the circuit on S1 must be closed. To set.... -
his month I am making 3 different types of siren circuits based on the 555 timer. The first circuit simulates the siren of a British police car. It uses two 555 timers in the circuit. The 555 on the right is wired as an alarm tone generator and the second.... -
A single hand clap will be picked up by the electric mic which is coupled through C1 into the op amp IC1. The output of IC1 triggers the 555 IC timer IC2 which is configured as a monostable multivibrater. The trigger pulse is stretched by IC2 and outputs a.... -
This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The receiver circuit is based on the Radio Shack infrared receiver module (MOD), part number 276-137. It is also available from some of the other sources listed on.... -
Pulse width modulation (PWM) is a technique to control analog circuits with a digital output. PWM is used in many applications, Specially to control light intensity and speed on motors. A PWM circuit makes a square wave with a variable width. The pulse width.... -
This is a simple oscillator with multiple resistors in serie. When you press any switch, the circuit starts oscillating. You can user variable resistors instead the 1k resistors. Using variable resistors you will be able to tune the frecuency for each note..... -
With this circuit we can create a altered sound of siren. The oscillator IC1a-b is constituted by two gates NAND, oscillating in very low frequency. This oscillation drive the IC2, that is a electronic switch, which opens and closes in the rythm of.... -
The circuit is based on the IC1 that is 555, for the creation of alternate flashes from the two led D1-2, that can be also different colour. The frequency of alternation can be regulated from the trimmer R3 and from the C1, if changes his capacity. The.... -
The modern mechanic switches are improved concerning of old technology. We need however many times to replacement some old switch or to check currents bigger than the durability of certain switches or simple we need something with modern appearance. For he.... -
A wide rage auto turn OFF timer covering 1 minute to 20 hours in three ranges with S1. As soon as power is applied to the circuit the IC1 [555] starts to oscillate happily and feeds clock pulses to the IC2 [4017]. The IC2 [4017] and IC3 [4020] give a.... -
The video switcher described here can display the output of two, three, or four cameras on a single monitor. The number of cameras is set by a DIP switch on the circuit board. That feature avoids blank displays if less than four cameras are used by.... -
The UNIVERSAL HOLD circuit detects the dual tone, multi frequency (DTMF) tone that is generated when the # key is pressed and then activates a circuit that partially loads the telephone line so that the central office thinks a phone is still off hook even.... -
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A simple SWR meter first needs a calibration to Uv = 100 % (forward power). When switching over to Ur (reflected power) the SWR is indicated. This procedure has to be repeated every time a change is made to the transmit power, antenna tuner or frequency etc..... -
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A Simple design based on a 555 to Drive a Car Ignition Coil. I Designed this for a Small Electric Fence to Protect my Vegitable Garden from some Small Animal called a Marmots. Last year they ate one of my crops entirely before I could install this device. A.... -
Here is a Simple Circuit to give a Flashing LED, With a "Rising and Falling" Brightness. It Uses the Sawtooth waveform from pins 2 and 6 to create the rise and fall. The Resistor and LED on Pin 3 are Optional. The 10K Potentiometer give a reasonable range of.... -
This project uses a four-point resistance measurement process also known as the Kelvin method. This procedure uses a current source to determine the value of an unidentified resistance. A constant current flows through the unknown resistance and the voltage.... -
This DC-to-AC inverter schematic produces an AC output at line frequency and voltage. The 555 is configured as a low-frequency oscillator, tunable over the frequency range of 50 to 60 Hz by Frequency potentiometer R4. The 555 feeds its output (amplified by.... -
The circuit is drawn for measurement of acceleration from 1000 mg until + 1000 mg. It can be placed in kantra'n the car and be supplied from the sheath of electric lighter. The circuit includes one indicative LED and a screen LCD. The measurement of.... -
This is basically a flasher circuit modified to turn on and off a bulb instead of a LED. It uses a 555 timer IC working as an astable multivibrator. The flashing rate can be varied from very fast to a maximum of once in 1.5 sec by varying the preset VR1...
New Circuits
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The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower..... -
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to....
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