Class A 40W into 8 Ohms Amplifier

Both parts of the circuit are biased with the constant current sources as shown, and the signal from the collector of the PNP is followed by the Darlington class A output stage whose idle current is controlled by the bias circuit. The transistors Q1 and Q2 form the traditional differential pair but there are some twists added to the feedback and input networks. The feedback circuit formed by R3 R4 R5 C2 C4 is used to bootstrap the input impedance to a nominal value of 40k Ohms while providing a low impedance path for the input bias currents. This results in a high input impedance with low offset voltage. The capacitor C4 creates a high frequency input to the negative feedback circuit which rolls off the high frequency gain of the amplifier...

Control the speed of a DC motor with a potentiometer with an Arduino board

A quick circuit showing how to control the speed of a DC motor with a potentiometer with your Arduino board. Also shows how to use a TIP120 transistor to allow the Arduino control a larger power supply...

Arduino Guitar Delay Pedal

An attempt at an Arduino guitar pedal. The guitar signal feeds through a PT2399 delay circuit, modified to include a JFET preamp phase. The delay circuit has Echo and Delay knobs. From there, it feeds into an optoisolated-Arduino-5V preamp, and out to the Arduino. The output from the Arduino is filtered and sent to the amp...

Guitar Effects / Pedal with arduino

Make your own Guitar Effects Pedal with an Arduino board. Bit crushing, rate reducing, weird noises. 10-bit effects/guitar pedal with an Arduino for lo-fi DSP..

There are several ways that "Caller`s Name" is used in public networks. ANSI has standardized two methods; one which sends the name during call setup and another which uses a database dip to look it up at the called end. The former utilizes an optional information element in an SS7 ISUP initial address message (IAM). The later uses SS7 TCAP messages to query an SCP...

Arduino Punk Console

A programmable 8 step tone sequencer using an Arduino microcontroller. Features a 2 line x 16 character backlit LCD display..

This cicuit allows you to test a servo. The angle of the servo can be set by means of the 10k potmeter. Perhaps you will not be able to reach all positions with this circuit. Playing with other resistors may help...

AutoTRAX EDA is a powerful multiplatform integrated Electronic Design Suite for Electronic Engineers. Starting with its easy to use Schematic Capture mode, you can drag pre-created parts onto your design sheets and rapidly and reliably connected the terminals together using wires, buses and off-page connectors...

Guitar Loop with Arduino

Build a Guitar Looper with an Arduino board. Here is how to produce pedalboard for electric guitar. The idea is to connect pedals to the Arduino, and to use them to control a software of sound processing in Pure Data. Here I show you the example of a looper, but one can be also made a rack of effects without problem...

In telemetry or security applications in which a modem connection automatically establishes itself between two systems, a failure in one of the systems can interrupt the data exchange while the connection remains established until someone physically breaks the line or restarts the failed system. This situation can also happen if your PC crashes during a long-lasting Internet download...

Arduino Motion Sensor

Give your Adruino board a motion sense around it! Use any Arduino board: Uno, Mega, Duemilanove etc. ..