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For a lower parts count than the 2 transistor multivibrators, 2 LED s can be alternately flashed with a 555 integrated circuit configured as shown in Schematic 2.  I chose the combination of a 2K2 and a 47K resistor to determine the oscillation frequency along with the 10 uF capacitor connected to pins 2 and 6. You can practically change the (R Speed) 47K value to between 10K and 100K or more. Greater resistance = lower speed. You may also wish to connect up a 100K or so potentiometer instead of the 47K resistor for a variable speed version. Additionally, the 10 uF capacitor value can be changed. Feel free to experiment. Although, alternately flashing LED s  is great for the beginner to electronics, the basic one ON, one OFF circuit gets boring quickly. In the next section, we will try to improve the look and try to approximate a flash like a police car (within limits).

The TV remote control transmits television signals as pulses of frequency around 37.5kHz. Each button on the remote control is pressed or equivalent has a pulse signal codes. This remote transmits pulses of the circuit block of the same frequency as the remote to your TV confuse decoding the transmitted signal. The heart of the circuit is the 555 timer IC in astable circuit works mode.The output series of pulses at a frequency of 18 kHz to 48 kHz by simply adjusting the 5K potentiometer. What you do is adjust the potentiometer until frequeny jives to its distance from the TV or until the signal is ignored by television. TV Remote Jammer Using 555 IC Circuit Diagram

This is a water sensor /rain alarm circuit diagram; it can be used on motorcycle, car or other device that we want to protect from water, rain. This is a simple water sensor/rain alarm circuit that makes an alarm when water/rain falls on its sensor. This circuit is based on NE555/LM555 IC and two transistors (Q1&Q2). For transistor Q1- BC547 or BC107 and for Q2- 2N825,BC548 or BC168 can be used in the circuit.  This rain detector circuit can be supplied from voltage source of +9V-12V DC. The resistor 470K ohm is a POT/Variable resistor; it is used to adjust the sensitivity of water/rain sensor. Use a 8 ohm,0.5w-1W speaker to hearing better alarm. Less than 8 ohm speaker could be harmful for the IC 555.  Circuit Diagram of Water Sensor   We can make the water sensor as shown in the image (Fig-1) using aluminu m conductor like a naked wire . Here can be used other conductor but we suggesting to use aluminum.

IC 555 timer tester is a simple circuit that serves to test the condition of IC 555. 555 timer circuit tester, in principle, start the timer 555 in astable multivibrator mode. As an indicator of the status of the timer 555 good condition or damaged to use 2 pieces LED which will light up in a blink alternately when the timer 555 in good condition.  And only one will turn on or off all the timer 555 when the condition is broken. 555 timer circuit tester is powered using 9 Volt DC voltage source. Complete circuit tester 555 as follows. Tester schematic How to use 555 timer tester is in conjuction with IC 555 to test the existing IC socket according to the orderbutton. Then activate the power switch to begin testing the 555 timer ic. Then live we observe the LED indicators 2buah before, whether flashing alternately (good) or not blink or even die all (timer 555 damaged).

The popular Timer IC 555 is extensively used in short duration timing applications. IC 555 is a highly stable integrated circuit functioning as an accurate time delay generator and free running multi vibrator. But one of the serious problem in 555 timer design is the false triggering of the circuit at power on or when voltage changes. The article describes how IC555 is designed perfectly to avoid false triggering. 555 IC pin functions Pin1 Ground Pin2 Trigger Pin3 Output Pin 4 Reset Pin 5 Control voltage Pin 6 Threshold Pin 7 Discharge Pin 8 Vcc Functional aspects of pins Trigger Pin 2 Usually pin2 of the IC is held high by a pull up resistor connected to Vcc. When a negative going pulse is applied to pin 2, the potential at pin 2 falls below 1/3 Vcc and the flip-flop switches on. This starts the timing cycle using the resistor and capacitor connected to pins 6 and 7. Reset pin 4 Reset pin 4 can be controlled to reset the timing cycle. If pin 4 is grounded, IC will ...

The series of police sirens with 555 ic this is a series of sirens that utilizes two IC 555 as a pulse generator and producing shrill voice.  Both ic 555 respectively build the astable multivibrator circuit and generate output signals with different frequencies. It is intended to be used as one of the high frequency generator or a screeching sound and the other as a regulator of the swing from last shrill voice. If we observe the working principle of this circuit is very similar to a series of modulation fm. Where the shrill sound signal likened to a high frequency signal from the oscillator circuit and control signal swing is the wail of the information signal or input signals that will transmit. This is consistent with the shape of the output signal associated with the loudspeaker, which has an output signal frequency changes in the form of regular meetings wave tenuous. Actually a series of sirens could be simpler than if you use a 556 IC which is a dual multivibrator or equal t...

This is a Simple Home Alarm Circuit Using 555 IC's . This circuit can be simplified by using a single 74C14 IC. This IC is also known by the following numbers: 40106, 40014, and 74HC14.  These are CMOS chips and are characterised by low current consumption, high input impedance and a supply voltage from 5v to 15v. (Do not substitute 7414 or  74LS14. They are TTL chips and operate on 4.5v to 5.5v and have low impedance inputs.)  Simple Home Alarm Circuit Diagram The 74C14 contains 6 Schmitt Trigger gates and 4 of these gates (Schmitt Inverters) are used in this circuit. The circuit consists of a number of "building blocks" and the first consists of two transistors in a very clever "bootstrap" arrangement. The first transistor is turned on via the 3M3 and 47k. The second transistor is not turned on and the output is HIGH. A small signal from the electret microphone will consist of positive and negative excursions and the negative excursion will turn the first tran...

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 DC-to-AC Inverter Schematic The 555 feeds its output (amplified by Q1 and Q2) to the input of transformer T1, a reverse-connected filament transformer with the necessary step-up turns ratio. Capacitor C4 and coil L1 filter the input to T1, assuring that it is effectively a sine wave. Adjust the value of T1 to your voltage. Error fix: Pin 7 and 2 were reversed. Original pinout was correct. Parts List: R1 = 10K R2 = 100K R3 = 100 ohm R4 = 50K potmeter, Linear C1,C2 = 0.1uF  C3 = 0.01uF C4 = 2700uF Q1 = TIP41A, NPN, or equivalent transistor Q2 = TIP42A, PNP, or equivalent transistor  L1 = 1uH T1 = Filament transformer, your choice The output (in watts) is up to you by selecting different components. Input voltage is anywhere from +5V to +15Volt DC, ad...

This is a Simple Bell Circuit with Two 555 Timers Project . This simple Bell circuit uses two 555 timers. The frequency is controlled by the capacitors that must be preserved almost identical in value to each other for best results. Fine tuning is done with R1 and R2. The decay time is controlled by R3.  Simple Bell Circuit Diagram

In many circuits we need to generate an internal adjustable voltage. This circuit shows how it is possible to use a trusty old NE555 timer IC and a bit of external circuitry to create a voltage inverter and doubler. The input voltage to be doubled is fed in at connector K1. To generate the stepped-up output at connector K2 the timer IC drives a two-stage inverting charge pump circuit. The NE555 is configured as an astable multivibrator and produces a rectangular wave at its output, with variable mark-space ratio and variable frequency. This results in timing capacitor C3 (see circuit diagram) being alternately charged and discharged; the voltage at pin 2 (THR) of the NE555 swings between one-third of the supply voltage and two-thirds of the supply voltage. Voltage Inverter Circuit Using IC NE555  The output of the NE555 is connected to two voltage inverters. The first inverter comprises C1, C2, D1 and D2. These components convert the rectangular wave signal into a nega-tive DC leve...

IC Timer 555 has a basic PWM controller with pulse width control feature 0 .. 100% which is controlled using the R1, at the time of controlling the oscillator frequency relatively stabi so it may be used to build the Simple PWM controller. Frequency of Simple PWM controller 555 depending on the value of R1 and C1, values ​​shown R1 and C1 will form the output with a frequency of 170 to 200 Hz. Diode-diode used in the Simple PWM controller With this 555 can use a 1N4148. R2, R3 and C3 form a giver triger circuit beginning at the reset IC 555 for 2 seconds. If you want to use a series of Simple PWM controller 555 with the V + not +12 V, it does not matter to raise tilapia R2 where (V + * R2) / (R2 + R3) is about 2, because it limits the signal level reset is 0.5 .. 1V. If you do not do that, then signal the kickstart to get too close to the limit reset signal reception. PWM controller circuit Q output of 555 on the Simple PWM controller circuit 555 is used for driver PWM pulse, so that t...