Simple Tools Help You Create A Better Circuit

introduction

Circuit design can be very difficult, because things in reality are very different from what we read in the book.Many circuits are combined from RLC, such as filter, dividing circuit, etc.

It seems simple, and it can be expressed in general equations, but in fact, it contains a lot of knowledge in design.Obviously, engineers need to continue to practice circuit design, and in the process

In order to exercise and correct, the circuit design work can be more efficient.Digikey's online small tools, not only related to the PCB line design, parts of parts of the part of parts

(Welcome to the previous article[Good helper from PCB to practice -online converter of digikey]  3) The super practical tools, at the same time, are also the circuit design.The following will be introduced, all

It is the most popular in the project. Take a look at your heart.

Figure 1: "Digikey's Online Converter" interface

The passive filter is used to attenuate signals higher than or below the determination frequency.This passive filter calculator allows you

Calculate -3DB dead frequency.According to the configuration of components, you can build a low or high -pass filter.The calculation method and line diagram corresponding to each combination type will be displayed in the calculator interface.Each filter

The description of the type is described in Table 1.

Filter type	Route diagram	describe
RC low -pass filter		The RC filter is the most basic filter to build blocks, which are usually used for low -power signal filtering.Because the load and the capacitor are connected in parallel, the load impedance is generally hypothetical, so the circuit has no load.
RC high -pass filter		Low -pass filter can be converted to high -pass filter and filter through the exchange resistance and capacitance.It can also be set to high load impedance circuit.
RL low -pass filter		The RL filter is another one -order filter combination.Because it contains inductance, it will produce phase shifts.It is generally used as a DC power supply for radio frequency amplifiers, where the inductor is used to transfer DC bias current and prevent RF back to the power supply.
RL high -pass filter		Low -pass filter can be converted to high -pass filter, filtering through the exchange resistance and inductance.

Example demonstration

ADI   AD7980  Pulsar® ADC series, the application line uses an anti -hybrid filter (Antialiasing Filter) combined with a 20Ω resistor and a 2.7NF capacitor

  ADC front.Because the ideal anti -hybrid filter is characterized by the unit gain in the band, there is no gain change, and the line is simple, so the RC filter is one of the good choices.Figure 2 is an example of the application line of AD7980.

Figure 2: AD7980 application line (data source: ADI)

If you want to find out the -3DB cut-off frequency of this filter, select "Low-pass filter" and "RC-resistor capacitors" in the tool, enter R = 20 OHM and C = 2.7NF, and get-3DB dead frequency 2.9473 2.9473MHz.

Sorter calculator 2

In the concept of many engineers, the pressure device circuit is just a circuit on the book. In the case, there is less opportunity to use it. Compared with the filter, the filter is more important, and it is, and it is, and it is, and it is, and it is, and it is more important, and it is, and it is more important, and it is, and it is, and it is more important, and it is more important.The design of the two different circuits has nothing to do with each other.But then carefully analyzes that the work of the filter is like a resistor from the resistance (R) and the capacitor electrical resistance 1/2πfc (taking the RC circuit as an example).In fact, there are many applications in the real circuit, and the application fields are also wide. For example, the logic level conversion of ADC, the environmental measurement of the sensor system, and the measurement instrument are all applied to the technology or concept of the pressure division.So this tool is loved by many senior engineers.The benefits of this tool not only provide basic non -load separation computing, formula and line diagram routine, but also to compare the situation when loading.

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Example demonstration

The use of the voltage voltage circuit is added to the front end of the protective element input, and the voltage rate ratio is used as one of the common applications to regulate the allowable input range of isolation elements.Figure 5 is  Broadcom   ACPL-C87As a circuit isolation element, the input terminal needs to be set to a voltage circuit, which is used as a voltage sensor, and the voltage ratio is used to control the optical isolation amplifier.Although the ACPL-C87 has a very high input impedance, this error cannot be ignored when the application of high precision instruments.In Figure 5, in the R1/R2 pressure device, R2 and RIN (input resistance of ACPL-C87X) are also deemed to be a downsor, which generates additional measurement error components.Using this tool, you can quickly know the error value of the load, so as to consider the acceptance of this error value to make line changes or adjust the resistance value.

SpecificationsApplication modulus gives R1 = 598kohm, R2 = 2kohm, and input impedance 1000mohm@2V.The calculation results are shown in Figure 6:

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Paid and series resistor calculator 1

In the design of the circuit, it is very common to use similar components and series in series. For example, the above -mentioned voltage voltage circuit is a series of resistance or the parallel of resistance in DAC.In reality, the applications of parallel and series are also extended to other types, such as LEDs or batteries. The parallel and or series of this component must be considered in design.Make changes, so make good use of this tool to save time -consuming complicated operations.The tools include two options: "parallel resistor" and "series resistor", which can also be added with a resistor to display the corresponding formula or line diagram examples, which is very convenient.

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Example demonstration

The following is how to calculate the total resistance of series and connect resistance.Suppose we have three resistors at the beginning, one 1000ohm, a 470ohm and a 680ohm.If they are parallel, their resistance value is in the tool input, and 217.4741 OHM is obtained.Figure 8 is the result display.

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If they are connected, their resistance values are in the tool input, and 2150 OHM is obtained.Figure 9 is the result display.

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Summarize

To design a hardware circuit of an electronic product, you need to carefully analyze, learn, and practice. In the areas of various components, the details of these components are designed and developed by engineers.Different circuit requirements in various fields, among each specialized, are also inseparable from some basic and practical circuits.We introduced the three practical and popular online tools of low -pass/high -pass filter calculators, pressure division calculators, and parallel and series resistor calculators. Use these small tools to make good use of these small tools will be a good helper!

For more technical information of the design and circuit design, please click the link below for refer to it. You are also welcome to leave a message to discuss at the end of the article.