The 555 integration is an integrated one used for many purposes. Oscillation is a stable integrated circuit that can be used to create time delay and pulse signal. The timing range can be between microseconds and hours. It also has a widespread use area with the provision of adjustable output frequency. The timer is the most preferred type of integrated circuitry. This integrated low cost has a stable at high frequencies. This is because the R and C elements connected to the integrated are selected at different values and the timing time is easily adjusted.
Pin and Comments
1) GND (Ground); It's the Earth Leg. It is called soil reference voltage. Voltage value; It's 0. 2) TRIGGER; It is called trigger leg in Turkish. When the voltage value at this input value drops to half the control voltage, a time interval begins and the output pin becomes HIGH 3) OUTPUT is called output leg in Turkish. Provides voltage about 1.7V below the supply voltage at the high output level. 4) RESET When this leg is LOW (Logic 0), the circuit resets. In addition, this leg is not connected to any leg. 5) CONTROL VOLTAGE This leg is connected to 2*Vcc/3 in the inner circuit. If desired, the timing period can also be changed by changing the voltage of this foot. Noise can be prevented by connecting to the soil with a capacitor with small capacity at normal operation. 6) THRESHOLD is called threshold leg in Turkish. If the voltage in this leg exceeds 2*Vcc/3, our output goes to LOW (Logic 0) and flip flop resets. 7) DISCHARGE is called discharge leg in Turkish. This leg is connected to the collector leg of an npn transistor in the inner circuit. It provides charging and discharge of the capacitor according to the change of resistances at high and low levels. 8) Vcc is called feeding leg in Turkish. Feeding voltage is applied from this leg. The feed voltage value can vary between 4.5 and 16V.
555 Integrated Features
• In addition to high stability and low cost, different features are available. These features include: • Turn-off time is less than 2 micro-seconds • Maximum processing frequency greater than 500 KHz • Provides timing from microseconds to hours • Can give high output current (200 mA) • Has adjustable output frequency • +4.5 , +18V feed voltage.
555 Timer Integrated Operation Modes
Translated into "Single Stable" mode in Turkish. In this mode, our 555 timer circuit acts as a "single pulse" pulse generator called "one-shot" in English. Monostable circuits are circuits that keep the circuit in a logial 1 (High-HIGH) state until a certain time when a signal arrives, triggered from the outside. The width of the output signal can be known by analyzing the RC circuit consisting of a resistance and capacitor. The output signal is interrupted when the voltage of the capacitor is 2/3 of the supply voltage. Thus, we can adjust the width of our output signal according to our R and C values.The time width of the output signal is 2/3 of the capacitor voltage; t = (RC)xln(3) = 1.1RC is calculated.
Translated into "Very Stable" mode in Turkish. This mode is also called Schmitt trigger mode. In this mode, our circuit works as a simple Flip Flop. Treshold leg, which is leg 6, changes simply, while our Trigger and reset pins (2nd and 4th in 555 circuits) Legs) are kept at a high level through pull-up resistances. Thus, when Threshold is connected to the ground, our trigger signal is instantly drawn into the ground and our output signal becomes logic 1 (High-HIGH). Our output signal will continue to maintain this status until the reset signal arrives. When our reset signal arrives, our output signal will remain logic 0 (Low-LOW) until our next trigger signal arrives. As the figure shows in this mode, there is no need for any capacitors. 5. We tie our leg to the ground through a small capacity capacitor.
Translated in Turkish as "Unstable" mode. This fashion can also be called working as an oscillator. Thanks to its operation as an oscillator, various applications can be made. In other words, applications such as flashing LED or lamp flander, Note tones, PPM applications, Safety alarm can be made by generating electrical signal. Another important feature is that it can be used as a simple ADC. So it can translate an analogue signal into a digital signal. Produces a square wave between logic 1 and locographic 0. The reason it is unstable is that its output remains continuous in a single state. The "C" capacitor is connected to the Trigger leg, which is pin 2. Thus, until our capacitor reaches 2*Vcc/3 Volt, our output end is in the case of logistics 1, i.e. HIGH.After our capacitor becomes 2*Vcc/3, our output becomes logic 0, i.e. LOW. We have come to the end of our article, but if you want a sample application, you can continue here.