Frequency counter using arduino

praveen February 19, 2015 18 Comments
Frequency counter using Arduino (upto 40KHz). Many guys here were asking for a frequency counter and at last I got enough time to make one.  This frequency counter using arduino is based on the UNO version and can count up to 40KHz. A 16×2 LCD display is used for displaying the frequency count. The circuit has minimum external components and directly counts the frequency. Any way the amplitude of the input frequency must not be greater than 5V. If...
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Motor speed control using arduino

praveen June 12, 2014 59 Comments
PWM motor speed control using Arduino. PWM or pulse width modulation is a very common method used for controlling the power across devices like motor, light etc. In PWM method the power across the load  is controlled by varying the duty cycle of the drive signal. More the duty cycle more power is delivered across the load and less the duty cycle, less power is delivered across the load. A hex keypad is used for controlling the speed. The...
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PWM Control using Arduino – Learn to Control DC Motor Speed and LED Brightness

praveen April 22, 2014 6 Comments
In this article we explain how to do PWM (Pulse Width Modulation) control using arduino. If you are new to electronics, we have a detailed article explaining pulse width modulation. We have explained PWM in this tutorial using 2 examples which will help you learn how to control LED brightness using PWM and how to control DC motor speed using PWM. PWM control using arduino. PWM control is a very commonly used method for controlling the power across loads....
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Simple audio circuits

jojo December 2, 2012 15 Comments
This article is a compilation of the simple and popular audio circuits we have published over years in CircuitsToday. This list involves a collection of simple amplifier circuits that you can try at home and some other audio related circuits with specific applications.  Image Source 1. 150 Watt amplifier circuit – This circuit is the most popular amplifier we have ever published. It has received over 700+ comments and is still counting. This amplifier has been tested by many...
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Audio oscillator circuit

admin February 22, 2012 16 Comments
ICL 8038 waveform generator. ICL8038 is a monolithic waveform generator IC that can produce sine, square and triangular waveforms with very little distortion. The frequency can be programmed from 0.001Hz to 300 KHz using external timing capacitor and resistor. Frequency modulation and sweeping can be attained by using an external voltage. Other features of the ICL8038 are high linearity, high level outputs, simultaneous sine, square, triangle wave outputs, low external parts count, high temperature stability etc. The working of...
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Class D amplifier circuit

admin November 7, 2011 6 Comments
Class D amplifier. Class D amplifier is a type of amplifier where the power devices (MOSFET or transistor) are operated as switches. There will be only two states (ON/OFF) for these switches and no time is wasted for the transition from one stage to another. The working of a class D amplifier is as follows. At first the audio signal to be amplified compared with a high frequency triangle waveform and the result will be a square wave whose...
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LA3161 Stereo Preamplifier

admin October 11, 2011 7 Comments
LA3161 Stereo Preamplifier. LA3161 is an integrated 2 channel pre-amplifier intended for car stereo applications. The LA3161 has a built in voltage regulator which plays a great role in improving ripple rejection . The IC requires minimum number of external parts and the noise level is very low. The IC has high input impedance (around 100K) and is available in an 8 pin SIL package. Description. In the circuit both of the built in amplifier section are used. Capacitors...
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Digital volume control circuit

admin August 9, 2011 19 Comments
Digital volume control circuit. MAX5486. A two channel digital volume control circuit based on IC MAX5486 is shown here. MAX5486 is a 40K dual digital volume / balance controller that has a pushbutton interface. The IC has a built in bias voltage source that eliminated the need of an external circuitry for the same purpose and thereby by reduces external parts count. The IC also has an LED status indicator driver circuit which can be used for driving the...
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100W MOSFET power amplifier

admin August 2, 2011 114 Comments
100W MOSFET power amplifier. A 100W MOSFET power amplifier circuit based on IRFP240 and IRFP9240 MOSFETs is shown here. The amplifier operates from a +45/-45 V DC dual supply and can deliver 100 watt rms into an 8 ohm speaker and 160 watt rms into a 4 ohm speaker. This Hi-Fi amplifier circuit is suitable for a lot applications like general purpose amplifier, guitar amplifier, keyboard amplifier. The amplifier can be also used as a sub woofer amplifier but...
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Multi-channel audio mixer circuit using LM3900

john July 27, 2011 6 Comments
LM3900 multi-channel audio mixer. A simple multi-channel audio mixer circuit using LM3900 quad amplifier is given below. The circuit consists of 4 channel quad amplifier (LM3900). Two mic audio inputs and two direct line inputs are available in this circuit. By adding the same circuit parallel with this, you can increase the number of inputs according to the applications. Each input is connected to the inverting terminal of LM3900.The built in amplifier of each section amplifies every audio input...
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