Envelope Detector Circuit with Separate Attack/Rise and Decay/Release Time Settings

Introduction to Envelope Detector Circuit Envelope detector circuit is used to get the amplitude profile of a signal. Some important properties of an envelope detector are attack or rise time and decay or release time. In the Figure 1, a signal is plotted in blue, and the detected envelope is plotted in black. Since it employs capacitor for filtering inside […]

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Automatic Wah/Quack Effect Using LED+LDR Controlled Band-Pass Filter

Introduction to Automatic Wah/Quack Effect Automatic wah/quack effect gives a similar effect with the manual version (reference [1]), but without the need of any pedal to manually control the frequency/tonal sweep. This automation is made possible by detecting the envelope signal of the instruments audio signal, and use it to control the filter to produce center frequency  sweep, producing audio […]

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Inductor-less Wah/Crying Baby/Quack Effect Using Operational Amplifier

A type of guitar effect pedal that produce “wah”- or “quack”-like sound, which is similar to the crying sound of  a baby is called  wah-wah pedal, or just  wah pedal. The effect is produced by filtering the musical instrument through a band-pass filter, which the center of its peak frequency is swept from low to high, mimicking  audio tonal transition […]

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Fold-Back Distortion: Producing “Phew” Effect Using Software and Hardware (Analog Electronic Circuit)

Introduction: What is Fold-Back Distortion? I was introduced to a term of  “fold-back distortion” in the past by an article from an old book which I forget what the title is, but the book contains schematic diagrams of many circuits collected from old publication of Elektor magazine (www.elektor.com). The article presents the circuit’s schematic diagram and how it works. I […]

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Symmetric Distortion Using Clipper Diodes for Guitar Effect

Introduction While almost every audio equipments  pay whatever it cost to minimize distortion, this kind of device does the opposite: distortion effect for electric guitar. Many methods have been implemented in producing a distorted signal from electric guitar pick-up, such as over-driven vacuum tube, solid-state (transistor), or diode clipper. The simplest form is passive diode clipper, which is implemented as […]

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High Voltage 220V AC Lamp Flasher Using 555 IC

Similar with previous high voltage  flip-flop circuit, this circuit controls high voltage (powerline) bulbs (220V AC). Instead of using transistors, this circuit uses NE555 integrated circuit, a very popular chip for timer or oscillator application. The required low voltage supply for 555 IC is provided by direct converter, made up by D1, R1, DZ1, and C1. This low voltage is […]

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Hi-Lo (Treble-Bass) Disco Lamp Controller

Using high (treble) and low  (bass) frequency  beat detection to control stage lamps can produce automatic light jockey for disco or any music performance. Instead of using general level of music signal to control a disco lamp, the circuit presented here uses two separate channel to give more complex variation of light flashing pattern. The dynamics of music signal is […]

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Low DC Voltage (12VDC) Fluorescent Tube Lamp Circuit

A fluorescent lamp, also called a fluorescent tube is a tube with electrodes filled with  low pressure mercury-vapor, utilizing fluorescence to generate visible light.  The excitation caused by electric current in the gas of  mercury vapor generate short-wave ultraviolet light. There is phosphor coating inside the tube an the  ultraviolet light then make this coating  glows.  Conversion of electrical energy into […]

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Audio-Controlled Disco Light Controller Circuit

Using some active and passive components, we can build a simple audio-controlled disco light controller circuit.  A standard audio power amplifier output, which usually drive loudspeaker, can used to drive this disco light circuit. With this circuit we don’t need light jockey anymore, because the flashing of the light will be directly controlled by the music signal itself.  The schematic […]

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High Voltage Flip-Flop With SCR and Low Voltage Components

With only few components, we can use resistors, diodes, and capacitor, we can convert line voltage (220VAC)  directly to low DC voltage (10 VDC). This low voltage powers the low voltage flip-flop standard circuit, but this circuit is then used to drive high voltage SCR. This simple high voltage flip-flop circuit can be used to control alarm lamps, bell, or […]

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CD4093 Switch-Mode Current Limiter for LED Driver

A LED driver provides power regulation so the working voltage and current applied to a LED is kept stable while maintaining high efficiency in various supply voltage condition. Using a Schmidt-trigger NAND gate, we can design a LED driver with switching technology. Switching technology is developed to minimize power loss power control. The idea of this technique is by fully […]

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Step-Up DC-DC Converter Circuit for Laptop Charger/Adapter, Convert 12V(9-14) to 19V(16-21V)

Step-Up Converter 12 to 19V for Laptop This DC-to-DC converter circuit enables automotive lead-acid battery to power your laptops/notebooks, converting 12VDC to 19VDC with good efficiency since it uses switching technology. I designed this circuit to make power backup for small home office  to provide eight hours backup for three notebooks.  The input voltage range is 9V to 15V, which […]

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