Voltage to frequency is very useful in many situation, such as transmitting temperature measurement using standard voice radio transceiver. This circuit (see the circuit`s schematic diagram) uses only two CA3130 op-amps, but the performance is good enough. The linearity of the voltage-frequency transfer is better than 0. 5% and the temperature coef
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ficient is lower than 0. 01% ! Assume that the output voltage of U1 is 15V, C1 will be charged with time constant (R9 R5)C1, flowing through R9, R5, D3, and C1. This charging will continue until the voltage of pin 2 (U1) get higher than the non-inverting input voltage at pin 3. After this, the output voltage of U1 will drop to zero (ground) and the non-inverting input pin 3 will drop to about 5V, set by the R3 for hysteresis. Now C1 will discharge its current through D4 and R6, at a rate determined by the voltage level at U2 output. If the C1 voltage has decreased below 5 volt then the U1 output will swing to 15V and the cycle will be restarted. At U1 positive input, the voltage level is the average of the pulse output of U1. The output of U1 is a positive pulse with constant width, and the space is variable depends on the discharging rate of C1 which is depend on U2 output. If the voltage level of this positive input of U2 is smaller than the control voltage at the negative input then the output of U2 will decreased toward negative supply (ground), therefore the discharging rate of C1 will be increased and the pulse output of the U1 will have shorter space, thus increase the voltage level at C3 until the it`s equal to the control voltage level at negative input of U2. If the voltage level at positive input is higher than the negative input, then the output of U2 will increase toward positive supply (15V) giving a reversed...
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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