Circuits using large value resistor/capacitor combinations are not very accurate because of the wide tolerance and leakage current of polarised capacitors. A better solution is to use an astable circuit together with a binary counter/divider chain which reduces the frequency of the astable pulses. The 4060 cmos integrated circuit is ideal for the games timer application. In this
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session, you will investigate how to set up the counter/display subsystem of the games timer using another cmos integrated circuit, the 4017 decade counter. To find out about the 4017, you need a source of pulses. You could use the 4060 astable circuit investigated in the previous session, but it is more convenient to build a temporary alternative circuit. About the easiest way of building an astable is using a special type of NAND gate, called a Schmitt trigger NAND gate. Here are the symbols for normal and Schmitt trigger gates: The Schmitt trigger gate has two different thresholds. If the voltage applied to one of the inputs to the gate starts at 0V and is slowly increased, the logic 1 threshold, when the input starts to count as a HIGH voltage, is around two-thirds of the power supply voltage, that is, about 6V with a 9V supply. On the other hand, if the voltage connected to the input starts at 9V and is slowly decreased, the logic 0 threshold, when the input counts as a LOW voltage, is around one-third of the power supply voltage, or about 3V. This difference in thresholds allows you to use a Schmitt trigger gate as the basis for an extremely simple astable circuit. The 4017 is a divide-by-10, or decade counter, with 10 individual outputs which go HIGH in turn when pulses are fed to its CLOCK input. The connection details for the 4017 are: To make the 4017 work, you need to connect the power supply pins (`beasties`...
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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