This circuit is a resonant twin-t filter. In this circuit, its purpose (according to the creator), is to give a decent fake lowpass response , which it does fairly well. Tim`s schematic shows two variations, one with self-oscillation, and one without. I built the one with oscillation. Since I was breadboarding it with a dual op amp (an NE5532,
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to be exact), I tried adding an overdrive-able input buffer/preamp, which worked pretty well, so I went with it. I had a plastic box sitting around with no lid, so I`ve temporarily built it into that for use with Loid. It will eventually become part of the piece I mentioned in the last post. Pots from left to right are: gain, cutoff, resonance. Here`s an audio demo, with the Q&D filter being fed with an XOR pseudo-ring mod, which in turn is being fed with two squarewaves from Schmitt trigger oscillators- at 1:06, the input is removed, and you can hear just the filter`s self-oscillation (modulation via 4069 LFO): Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser. These circuits currently exist on Loid`s breadboard extension. As I`m out of space in the containers, and am also reaching the limit of the power supply I`m using, Loid will be getting another piece added soon. In addition to the modules discussed here, I also plan to add a 4017-based sequencer, a noise source, a couple of VCO`s, and most likely some other stuff. If all goes according to the current plan, the result will be a sort of utility/ brain-box , which will also function as a take-away sequencer and beat box. The simple VCA is in this series of pages, towards the back of the book . This is from a project Ray Wilson was involved...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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