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Speed ​​Control of DC Motor PWM Circuit Diagram. Often, people try to control small DC motors with a variable resistor type potentiometer connected to a transistor. This system until works well but it generates heat and thus loses power. This circuit is a simple circuit for modulating the pulse width for controlling the DC motor, it eliminates this problem.  Speed ​​Control of DC Motor PWM Circuit Diagram The circuit is capable of controlling the engine speed pulses (PWM), these pulses have a duration variable to change the speed of the motor. The longer the pulses lead, the faster the motor will rotate, and vice versa. R1 1 Meg 1/4W Resistor R2 Potentiometer 100K C1 0.1uF 25V Capacitor Ceramic Disc C2 0.01uF 25V Capacitor Ceramic Disc Q1 MOSFET IRF511 or IRF620 U1 4011 CMOS NAND S1 KEY M1 Motor  The resistor R2 adjusts the speed of the oscillator and thus the speed of the motor, the motor can be any DC motor that operates from 6V and having no more powe...

Advantages, disadvantages and application of FET over BJT Advantages 1.        FET gas high input impedance of several mega ohms. 2.        The noise produced by a FET is less than that produced by a BJT. 3.        FETs are less effect by radiation compared to BJT. 4.        FET has no offset voltage at zero drain current and hence it forms an excellent signal chopper. 5.        FETs are voltage controlled devices. 6.        FETs have better thermal stability. 7.        In the integrated circuit form FET is simpler to fabricate and it occupies less – space. Disadvantages FETs have a drawback of smaller gain bandwidth product compared to BJT. Applications The high input impedance and low output impedance and low noise level make FET for superior of the bipolar transistor. Some of t...

      The P-N junction diode is appeared in the year 1950. It is the most essential and the basic building block of the electronic device. The PN junction diode is a two terminal device, which is formed when one side of the PN junction diode is made with p-type and doped with the N-type material. The PN-junction is the root for semiconductor diodes. The various electronic components like BJTs, JFETs, MOSFETs ( metal–oxide–semiconductor FET ), LEDs and analog or digital ICs all supports semiconductor technology. The main function of the semiconductor diode is, it facilitates the electrons to flow totally in one direction across it. Finally, it acts as a rectifier. This article gives a brief information about the PN junction diode, PN junction diode in forward bias and reverse bias and the VI characteristics of PN junction diode What is a PN Junction Diode? There are three possible  biasing  conditions and two operating regions for the typical PN-Junctio...

Working of D.C Generator As explained before the D.C generator converts mechanical energy into electrical (D.C) energy. The generator is usually coupled to a prime-mover. The prime-mover may be a diesel/petrol engine, or a turbine depending upon the rating and application of the generator. The prime-mover converts some sort of energy (diesel/petrol/water/steam/gas etc.) into mechanical energy. This mechanical energy is supplied to the generator (i.e. generator input). Working of D.C Generator If the generator is very small for commercial purpose i.e. for a shop or small work shop or cinema etc. the prime-mover is a diesel engine. If the generator is very big like in power stations then the prime-mover will be a turbine. Again depending upon the resources the turbine may be a water turbine, steam turbine, gas turbine etc. When the prime-mover output is given to the generator, the generator armature starts rotating. Usually the poles on the yoke are made of permanent magnets. Therefore, ...

Pointers and Scales in Measuring Instruments Instrument scales and pointers may be considered together in two classes: (A)     Those intended for reading quickly (in the case of switch board instruments at a distance), and (B)      Those intended for close accurate reading for portable instruments. Pointers: The shape and size of the pointers depends upon the type of instrument. The weight and inertia of pointer must be reduced so as to reduce the load on the bearing and to avoid necessity of damping torque. The pointer motion is usually limited by buffer stops little more than the scale. These stops are constructed as very light springs so that the pointer is not bent when it strikes them sharply on a sudden overload or reversal of the operating current. fig 1. Pointer The pointers for switch board and panel instruments should be so that the position of the pointer is conspicuous. The pointers are usually broad or carry broad targets at their ends. Al...

    According to unofficial data, LG plans to abandon the line of devices G Pro, focusing on the future of LG G4. The first device series G Pro appeared a few years ago, the company attempted to take place in the market "planshetofonov." However, the same LG G3, for example, has a 5.5-inch display, so little need for new LG G Pro no longer assume in Phandroid. In the case of a single leader it can be to provide the best set of components. You do not have to fear that another top-end machine (but the other line) entice potential buyers. In addition, the only profitable to promote a top gadget than a few of these. It is worth noting that a similar strategy chosen by Sony and Samsung, ready to cut the range of mobile devices for improving business performance. Also adds intrigue registered trademark of LG G Pen. Its scope is unclear, as is mentioned in the description of almost everything that is somehow related to electronics. Similarly, the situation with the trademark G Scraw...

Classification of Amplifiers Amplifiers are classified in the following ways. 1.        According to the Type of Load Impedance:   According to this method of classification amplifiers may be classified  as         (a)      Un tuned amplifiers         (b)      Tuned amplifiers           Un tuned amplifiers may further be classified as                         (i)       Audio frequency amplifiers                         (ii)      Video frequency amplifiers  Tuned amplifiers may further be classified as                         (i)        Single tuned amplifiers             ...

This is a very simple Electronic Circuit Project of piezo alarm circuit. Piezo alarm which will generate a sound around 110dB can be designed using this diagram. This Piezo alarm siren circuit diagram use some common components like 555 timer ic, you can use two 555 timer circuits or one 556 circuit. Electronic Alarm Project of Piezo with 555 Timer Circuit Diagram: This Piezo alarm siren circuit project use two piezo sounders with high efficiency and can be powered from a wide input voltage, between 5 and 15 volts. This circuit is very easy to build, maybe you will have a little trouble with the T1 and T2 auto-transformers. Both auto-transformers used in this project are the same type and require between pin 1and 2 1500 turns of 44 SWG wire and 220 turns between 2 an 3 using 40 SWgG wire. In this circuit the IC1:B closest to the piezo elements is set to oscillate around their resonant frequency. The frequency is then varied via input pin 11 from the other 555, IC1:A. This modulating in...

Differential Amplifier A differential amplifier serves to amplify the difference between tow signals. A differential amplifiers forms the basic stage of an integrated op-amp with differential inputs. The circuit diagram of the emitter coupled differential amplifier is shown in the below fig. it uses two identical npn transistors. The transistors are connected in CE mode. The emitter bias is used here. The two inputs V 1 and V 2 and the output is V o . The output is derived from the two collector points. If the inputs are similar, the output of the amplifier is zero. The amplifier outputs V 1 and V 2 . Therefore it is called as differential amplifier. The emitter coupled differential amplifier of the below fig possess the following properties. Emitter Coupled Differential Amplifier 1.        Low drift. 2.        Very high input resistance. 3.        Cancels the effects of supply voltages. 4. ...

I have a circuit where I want to have a constant current of 2mA through a variable resistor. I've been told that I could probably use a LM317 as a current regulator, with one resistor on the ouput. But I've read some places that the LM317 takes minimum 5-10mA load to function correctly. How can I achieve a constant current output of 2mA when I don't know the resistance of the variable resistor? The input voltage is about 2.755V. Output voltage doesn't matter, just the current. Here's an image to my feeble attempt at a schematic: The LM317 with the single series resistor between output and adjust input is actually a fixed current source, not a current limiter. You don't need the LM317 to create a current limiter, a few discrete components will do: For a limiting at 2mA you select a 330 Ω resistor for R S E N S E . If there flows 2mA through it Q2 will start to conduct and reduce the base voltage of Q1, so that its current is cut off. edit (re changed question) ...

Classification of Measuring Instruments Measuring instruments may be broadly classified as follows 1.        Absolute instruments 2.        Secondary instruments (a)      Indicating instruments (b)      Integrating instruments  (c)      Recording  instruments Absolute and secondary instruments   Absolute instruments: “absolute instruments are those which gives the value of the quantity to be measured, in terms of the constants of the instruments and their deflection only”. Such instruments do not require any previous calibration or comparison. Example: Tangent galvanometer (is a very common example) and Rayleigh’s current balance instruments. Uses: These instruments used as standardizing instruments in laboratories. Secondary instruments: “secondary instruments are those in which the value of electrical quantity to be measured can be determined from the...