This circuit produces a sound similar to the police siren. It makes use of two 555 timer ICs used as astable multivibrators. The frequency is controlled by the pin 5 of the IC. The first IC (left) is wired to work around 1Hz. The 47uF capacitor is charged....

The timer circuit shown gives independent control of the output`s on and off intervals, which can range from 0. 055 seconds to 30 minutes, relatively unaffected by power-line transients. IC1 is a CMOS programmable-timer chip that includes 24 ripple-binary....

get it on and off continuously. The circuit is using a well known NE555 timer IC which is a very famous IC due to its uses in the wide variety of electronic circuits. In this circuit this IC is connected as a astable multivibator and the 12 volt relay is....

The IC tester in this web site is specially designed for the timer IC LM555. this circuit is used for testing timer IC. circuit diagram and technique of various project ...

circuit of burglar alarm using IC timer 555/556 is functioned as an alarm to prevent thief entering your house. The alarm would produce loud sound when a thin wire connecting resistor R1 with IC pin no 4 is broken. Thin fiber is used as the wire. The thinner....

This application uses the timer connected for astable (free-running) operation, with a modulating signal again applied to the control voltage terminal. The pulse position varies with the modulating signal, since the threshold voltage and the time delay is....

The post explains a simple delay ON circuit which allows the connected load at the output to be switched ON with some predetermined delay after power switch ON. The explained circuit can be used for all applications which calls for an initial delay ON....

The program in the microcontroller knows two protocols; the one wire bus used by the DS1820 temperature sensor, and the serial protocol expected by your computer. Once power is applied, the program fetches data from the sensors and sends it to the serial....

Manufacturers of cordless drills generally recommend a battery charging time of three hours. Once the charging time is up the battery must be disconnected from the charger: if you forget to do this there is a danger of overcharging the battery. This circuit,....

This is a single zone alarm - with automatic exit, entry and siren cut-off timers. It will accommodate all the usual types of normally-closed input devices - such as magnetic reed contacts, foil tape, PIRs etc. But it`s easy to add a normally-open trigger.....

This time delay relay circuit is built with IC NE/SE555, produced by Intersil which contains a precision timer. Stability to temperature variations is 0.00...

can be arranged in a circle to represent the 12 hours of a clock face and an additional 12 LEDs can be arranged in an outer circle to indicate 5 minute intervals within the hour. 4 additional LEDs are used to indicate 1 to 4 minutes of time..

The purpose of this circuit is to power a lamp or other appliance for a given time (30 minutes in this case), and then to turn it off. It is useful when reading at bed by night, turning off the bedside lamp automatically in case the reader falls asleep After....

This circuit calls more Free Running Multivibrator work resemble Flip Flop. Which encourage itself repeatedly. The Q1 and Q2 be Transistor PNP be usable general (2N3906, 2N2907, etc. ) The R1 and R2 limit current that flow through LED the bilateral. If....

This circuit is a monostable multivibrator, or one-shot, made with a 555 timer chip. Click the logic input on the left (the "H"), and the output goes high for a short time, and then it goes low again. A timing interval starts when the trigger input ("tr") is....

This circuit is built around a 555 timer using very few components. Since the circuit is very simple, even a novice can easily build it and use it as a co....

Timers are widely used in industrial and domestic application for automating tasks. Microcontrollers can be used to design versatile and accurate timers with...

This is the circuit of a low power LED night lamp that will automatically switch OFF at day time. The CMOS timer IC TS555CN is wired as a square wave generator operating at around 5Hz. The output voltage from the IC1 is doubled using the combination of....

The charging circuit stops automatically when the battery is fully charged. So you can leave the emergency light connected to AC mains overnight without any fear. The circuit can be divided into inverter and charger sections. The inverter section is built....

This project introduces important type of transducer, an optical coupler. An optical coupler together with a square wave generator and counters can be used to construct a timer for appliances. That is, an appliance can be turned on at a desired time for a....

This is the sequence timer diagram composed by NE555. The timer can set time any time when the power is connected, break and control the external system to work. In the circuit, K1-K3 are relays used to control the corresponding system to work, adjust the....

This circuit`s frequency of oscillation increases directly with light intensity. The greater the light intensity, the higher the frequency of the oscillator. The 555 timer operates in the astable oscillator mode where frequency and duty cycle are controlled....

The water sensor circuit is based on a 555 timer circuit and come common electronic components. The water sensor is made by two metal electrodes arranged very close that a drop of water (liquid) will bridge them. If the liquid ( water ) is very pure you may....

For many applications it is necessary to delay signals. Just think of applications in automation and control systems. Such a signal delay circuit can be set up with two monoflops....

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This instructable started with my previous camera hack making a remote shutter release. I found a 555 timer tutorial and realized how great it would b....

In this circuit a standard op-amp is wired as an astable multivibrator. The output is non-symmetrical but has the advantage that the timing is controlled by only 1 resistor and capacitor, in this case, the 100k variable resistor, U2 and 100u capacitor C1.....

The next job is the LNA transistor replacement, but the trouble is repeated already within next contest. Such problem is usually result of unsuitable time sequence of switching between receive and transmitting, where due to different delays (for example by....

This is a circuit for touch switch circuit. This circuit is almost same with touch door alarm. This circuit uses a 555 timer as the bases of the touch switch circuit. This is the figure of the circuit. The operation of this circuit is begin, when the plate....

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These two circuits make a LED fade on and off. The first circuit charges a 100u and the transistor amplifies the current entering the 100u and delivers 100 times this value to the LED via the collector-emitter pins. The circuit needs 9v for operation since....

Instead of the 555 timer IC we have two transistors back to back acting as a multivibrator. This "chops" the direct current enough so it can travel across the magnetic field of the transformer. This is probably the simplest and easiest stun gun to make. It....