Free electronic circuit design and schematic diagram
What we can do with a stereo voltage-controlled volume control? There so many things, we can control our audio using a DAC which is controlled by a microcontroller, or we can use mono potentiometer with RC filter to minimize the scratched sound produced by a dirty potentiometer (I see this method in one of SONY audio products). Using a voltage-controlled […]
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Current loop interface has been widely used in industrial environment because it’s robustness. Noise resistance and fail detection capability made it suitable for long distant transmission in harsh environment. This circuit provide current loop transmitter for temperature sensor. Here is the circuit’s schematic diagram: The temperature measurement is done by LM35 temperature sensor chip. You can use general silicone diode […]
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If you send a DC voltage signal to carry the information for a long distance, then the signal will suffer attenuation with unpredictable characteristic introduced by the medium, for example the cable resistance that vary with temperature changes. If you carry the information with frequency, not a DC voltage level, then the frequency will be stable even though it’s amplitude […]
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If you have a digital voltmeter, or any voltmeter with millivolt resolution and high input impedance, then you can use this temperature-to-voltage adapter circuit to measure room temperature. Here is the circuit’s schematic diagram: Note that the voltage output of this circuit is floating, not referenced to ground. You have to use separate supply if your voltmeter has single ended […]
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Operational amplifiers for tone control circuit application require high slew rate, wide bandwidth, high input impedance, and high output current characteristics, and CA3140 is suitable for this purpose. Look at the following tone control circuit’s schematic diagram for the design. The tone control circuit in the figure above use a very popular Baxandall tone control configuration circuit, which has unity […]
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The schematic diagram shown in the figure below show a function generator circuit using CA3130 in the integrator the threshold detection sections. Both triangular and square-wave signal are available from this circuit’s output, ranging from 0.1Hz to 100KHz (1:1000000 ratio). This frequency adjustment is done only by a single control R1. A voltage control input is available for externally-controlled frequency […]
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One of the interesting features of CA3130 op-amp is its high input resistance, because using such high input resistance, we can build an astable multivibrator with high R/C ratios. The figure below shows the circuit’s schematic diagram, you can see the variable resistors to adjust the “on” and “off” periods independently. Resistors R1and R2 are used to bias the CA3130 […]
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