AmplifierCircuits

A simple method of deriving a center or third channel without the use of an extra transformer or amplifier, (a) 4- speakers are connected to 8- amplifier taps. 8 and 16- speakers connect to 16- taps, (b) By blending the inputs it is possible to cancel out undesired crosstalk. Derived Center-Channel Stereo System

When this circuit is connected to a filter and an oscilloscope, the scope displays the filter`s frequency response. Afrequency that sweeps from low to high is applied to a filter. An oscilloscope is triggered by* the start of the sweep and ends its trace at the highest frequency of the sweep. The filter output goes to the vertical amplifier of the oscilloscope. Using bandpass filters as an example, as the bandpass frequency is approached, reached, and passed, the scope follows the peaking output and draws the response curve. A neat effect! The 566 VCO (Ul) produces a VLF triangle wave to frequency modulate the next stage. It also produces a square wave to externally trigger the scope. Op amp U2 (a 741 unit) optimizes the amplitude and the dc component. Another VCO (U3) produces the actual sweeping triangle wave. Its frequency is selectable via SI. Op amp U4 (another 741 op amp) is set up as a bandpass filter and has been included as an example filter. Finally, diode D1 chops off the b...

The circuit as shown gives the bandpass operation the transfer function calculated from FBP(s) = where = 1 + s/Qo>0 + s2/w02. The cut-off frequency, 0, and the Q-factor are given by 0 = g/C and Q = gR/2 where g is the transconductance at room temperature. Interchanging the capacitor C with the resistor R at the input of the circuit high-pass operation is obtained. A low-pass filter is obtained by applying two parallel connections ctf R and C as shown in Fig. 2. The low-pass operation may be much improved with the circuit as given in Fig. 3. Audio Filter Circuits Here the gain and Q may be set up separately with respect to the cut-off frequency according to the equations Q = 1/fB = 1 + R2/R!, A = Q2 and 0 = g ffi/C.

A UART is usually an individual (or part of an)  integrated circuit  used for  serial communications  over a computer or peripheral device  serial port . UARTs are now commonly included in microcontrollers. A dual UART, or  DUART , combines two UARTs into a single chip. An octal UART or  OCTART  combines eight UARTs into one package, an example being the NXP SCC2698. Many modern ICs now come with a UART that can also communicate synchronously; these devices are called USARTs  (universal synchronous/asynchronous receiver/transmitter). Programing UART in ARM Microcontrollers: you can find here:  www.gadgetronicx.com

So, the microcontrollers today offering a more and simple solution our lives. One of the controllores is LPC11Cx2. The LPC11Cx2/Cx4 are an ARM Cortex-M0 based, low-cost 32-bit MCU family, designed   for 8/16-bit microcontroller applications, offering performance, low power, simple instruction set and memory addressing together with reduced code size compared to  existing 8/16-bit architectures. The LPC11Cx2/Cx4 operate at CPU frequencies of up to 50 MHz.  The peripheral complement of the LPC11Cx2/Cx4 includes 16/32 kB of flash memory,  8 kB of data memory, one C_CAN controller, one Fast-mode Plus I2C-bus interface, one  RS-485/EIA-485 UART, two SPI interfaces with SSP features, four general purpose  counter/timers, a 10-bit ADC, and up to 40 general purpose I/O pins. On-chip C_CAN drivers and flash In-System Programming tools via C_CAN are included.  In addition, the LPC11C22 and LPC11C24 parts include an on-chip, high-speed CAN transceiver.  ...

arduino .cc/en/uploads/Main/ Arduino _Uno_Rev3- schematic .pdf

This article is about a simple auto ranging ohmmeter using arduino. The measured resistance is displayed using a 16×2 LCD display. The circuit is sufficiently accurate and uses minimum number of external components possible. Before going into the details of this project, lets have a look at the basic resistance measurement method. Resistance measurement. The figure above shows the circuit diagram of a simple resistance measurement scheme. Rx is the resistance to be measured. R1 is the input resistance. i is the current passing through the loop and 5V is the supply voltage. To find the unknown resistance Rx, the voltage across Rx is measured first. let the voltage across R1 be VR1. Then VR1=5-Vx. The current i=VR1/R1=(5-Vx)/R1. Since R1 and Rx are connected in series, the current through them will be equal. So the unknown resistance Rx= Vx/i. The voltage across the unknown resistance is measured using the ADC of the arduino. To be precise, analog channel A5. Anyway this me...