Counter Circuits
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The oscillator provides a 1MHz and a 1khz clock. The 1MHz clock is used as the clock for the microcontroller and as timebase for millisecond measurement. I use a 2MHz and divide it by 2 in order to guarantee a 50% duty cycle. Then three halve HC390 are used.... -
After getting some Micro Scalextric for Christmas and shortly after acquiring a vast mount of second-hand track from eBay I decided I needed a lap counter so I could race against the clock with opponents. I didn`t just want to see who could do 10 laps first.... -
This is a successor of the PIC16C71 4-digit LED f-counter & V-meter. Some hard to find parts used in the previous version, which are out of production for some time, has been omitted. A rather early PIC16C71 has also been replaced by 28-pin device PIC16F876..... -
This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a "ding-dong" chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors. The Holtek HT-2811 is available.... -
As equipment becomes increasingly more compact, designers are often obliged to follow suit by reducing the size of displays. At some point, the usefulness of the display can become compromised. I, for one, dislike having to peer intently at tiny displays in.... -
I needed an excuse to use the soldering iron so I figured that I might as well as make a frequency counter which is something that I`ve always wanted, but lacked in my lab. Here`s the schematic. I drew it up in OrCAD PSpice a while back. Since then, I have.... -
Measuring the radiation can be made not only with expensive factory-made instrument. The simplest device (see Figure 1), can be build if you have a counter (radiation detector) type SBM-20 or similar. The circuit is powered by a 220 volts AC 50/60Hz. The....
New Circuits
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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.....
Popular Circuits
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1.25 ~ 37V as shown for the adjustable power supply circuitry. It is adjustable three-terminal...