Matt circuit

9V battery operated add-on unit for moving magnet pick-ups Two-stage Series/Shunt feedback RIAA equalization This unit was designed for amateurs owning an old collection of vinyl recordings and wanting to have it digitally remastered into a personal computer. Or sometimes they would listen to an old, invaluable, LP collection through their modern High Fidelity chain, usually lacking a phono preamp stage: this is a circuit capable of satisfying their needs. The unit is powered by a 9V battery, allowing a quick and easy connection to all high-level input preamplifier stages and the very low current drawing of the circuit will guarantee a long battery life. Circuit diagram : Portable Phono Preamplifier Circuit Diagram Despite the low voltage supply, circuit performance with moving magnet pick-ups is quite good, featuring high input overload capability, very low distortion and accurate reproduction of the RIAA equalization curve, thanks to a two-stage op-amp circuitry in which the R...

There are many 9V chaser circuits that seem to waste about 7V when driving LEDs that are only about 2V. This project is unique, because it uses only two inexpensive alkaline battery cells totaling 3V for power. Since most of the waste is eliminated, the cells last a long time.    Unlike the other circuits, this one flashes the LEDs for only about 30ms each, further extending the battery life. For user convenience, it has a stepper speed control and a brightness control. At slower speeds and with reduced brightness, the battery life is further extended considerably. Mounted in a circle, the LEDs appear to rotate as they step from one to the next. Specifications • Battery: Two alkaline cells (AA size were used in the prototype) • Battery Life: AA cells C cells D cells Minimum speed and brightness 8 months 2 years 4.9 years Medium speed and brightness 6 months 1.5 years 3.6 years Maximum speed and brightness 2 weeks 1.5 months 3.6 months • Stepper speed: 2 LEDs/sec to...

In communications receivers and microphone amplifiers for transmitting equipment, there is frequently a need for a narrow, low-frequency band-pass filter that lets only the voice band through. This band is usually defined to be the portion of the audio frequency spectrum between approximately 300 Hz and 3300 Hz. In order to implement such a filter, we have calculated the values for two fifth-order Butterworth filters having these corner frequencies and connected them in series. The result is a band-pass filter for the desired pass-band with a skirt steepness of 100 dB/decade.  The first opamp (IC1) acts as a buffer. Speech Filter Image : The circuit can be powered by a unipolar supply voltage between 5 V and 18 V, which is a broad enough range that it should always be possible to find a suitable voltage when building the filter into existing equipment. The current consumption of the filter is only a few milliampères, which should rarely pose a problem. There is fairly wide select...

Using the FAN 7710 Ballast Control IC for Compact Fluorescent Lamps developed using Fairchild’s unique highvoltage process and system-in-package (SiP) concept can be designed a very simple low cost fluorescent lamp driver electronic project .The FAN7710 ballast control controls internal high-voltage stress and delivers 20W to the lamp at 320VDC voltage. FAN7710 ballast control incorporates a preheating /ignition function, controlled by an user-selected external capacitor, to increase lamp life. The FAN7710 detects switch operation from after ignition-mode through an internal active Zero-Voltage Switching (ZVS) control circuit. The AC line input voltage (230 VAC 50 Hz) is rectified to provide a bus voltage of approximately 320 volts DC. Startup resistor R1 supplies initial power to the FAN7710 IC.The IC begins to oscillate and the charge pump circuit consisting of C2, D2 and D7 supplies the current to the VDD pin, which gets regulated through the internal 15-V shunt regulator.

This is simple and Low-cost circuit diagram project of simple power mosfet inverter circuit. This inverter can deliver .high-voltage ac or de, with a rectifier and filter, up to several hundred volts. Low- Cost Power Mosfet Inverter Circuit Diagram: The secondary and primary of T1-a 12.6 to 440 V power transformer, respectively-are reversed; e.g., the primary becomes the secondary and the secondary becomes the primary. Transistors Q1 and Q2 can be any power FET. Note: Be sure to heat sink Q1 and Q2. Capacitors C1 and C2 are used as spike suppressors.

If you want to operate power LEDS with a truly constant current which significantly prolongs the lifetime of the lamp and avoid the power loss resulting from using a constant voltage supply with a series resistor, you need a suit-able constant current source. However, the only way to achieve really good efficiency is to use a switching regulator. Altogether, this means that you need a switching regulator designed to generate a constant current instead of a constant voltage. With this in mind, the author started working on the development of a LED pocket torch with especially high efficiency. Along with using high-capacity rechargeable batteries to maximise operating life, it’s worthwhile to be able to reduce the brightness, and therefore the operating current of the LEDs, when you don’t need full power. Accordingly, the author incorporated a dimming function in the design, based on operation in PWM mode in to reduce power losses to an absolute minimum. Power LED Driver Circuit Diagram ...

This Outdoor LED Solar Garden Lights project is a hobby circuit of an automatic garden light using a LDR and 6V/5W solar panel. During day time, the internal rechargeable 6 Volt SLA battery receives charging current from the connected solar panel through polarity protection diode D9 and current limiting resistor R10. If ambient light is normal, transistor T1 is reverse biased by IC1 (LM555). Here IC1 is wired as a medium current inverting line driver, switched by an encapsulated light detector (10mm LDR). Multi-turn trimpot P1 sets the detection sensitivity. When ambient light dims, transistor T1 turns on to drive the white LED string (D1-D8). Now this lamp load at the output of T1 energizes. Resistors R1-R8 limits the operating current of the LEDs. When the ambient light level restores, circuit returns to its idle state and light(s) switched off by the circuit. Circuit diagram: Outdoor Garden Solar Lights Circuit Diagram Assemble the Outdoor Solar Lights circuit on a general pur...