www.kn34pc.com

www.daycounter.com: Decibels (dB) Calculator
www.daycounter.com: Electronics Calculators Index

www.analog.com: VRMS/dBm/dBu/dBV calculators
www.analog.com: ADIsimDDS (Direct Digital Synthesis)
www.analog.com: Analog Filter Wizard

RF Converter

Custom Character Generator for HD44780 LCD Modules
LCD Custom Character Generator.Support character lcd and create code for Arduino
8x5 online custom character generator for Arduino LCD

Hexadecimal Decimal Binary Octal Converter for programmers

RF Unit Converter, make conversions between common RF units

Расчет П-контура

IP Subnet Calculator

LCD Addressing:
http://web.alfredstate.edu/faculty/weim ... index.html

dBm to Volts Conversion Calculator

Ето и два калкулатора, които ползвам сравнително често:

Превръщане на децибели:
http://www.sengpielaudio.com/calculator-db.htm

Изчисляване на LC филтри:
http://www.wa4dsy.net/filter/filterdesign.html

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Тук има удобна табличка за dBm:
http://wera.cen.uni-hamburg.de/DBM.shtml

Chebyshev Lowpass Filter Designer (и др.)
http://www.changpuak.ch/electronics/che ... owpass.php

Calculatoredge
http://www.calculatoredge.com/electroni ... 20pass.htm
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Quick and Easy Bandpass Filters for Receiver Input Tuning - George Dobbs G3RJV
http://www.gqrp.com/technical1.htm

PY2OHH, FILTRO PASSA BANDA BPF (BAND PASS FILTER)
http://py2ohh.w2c.com.br/trx/bpf/bpf.htm

Поредният удобен калкулатор за изчисляване на еднослойни бобини с въздушна междина:
http://www.changpuak.ch/electronics/calc_21.php

Калкулатор в Excel за двукръгови диапазонни филтри.

Диапазонные полосовые фильтры:
http://forum.andys.ru/threads/Диапазонные-полосовые-фильтры.361/
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Многократно съм използвал и пресметнатите стойности на компонентите за диапазонни филтри от страничката на PY2OHH:
http://py2ohh.w2c.com.br/trx/bpf/bpf.htm

Design Theory:
http://www.hagtech.com/theory.html#bandpass

Онлайн калкулатори за ... всичко:
http://www.calculatoredge.com

ОНЛАЙН РАСЧЁТ ПОЛОСОВЫХ LC - ФИЛЬТРОВ
КАЛЬКУЛЯТОР ПОЛОСОВЫХ LC - ФИЛЬТРОВ ЧЕБЫШЕВА 3-ГО, 5-ГО И 7-ГО ПОРЯДКОВ
http://vpayaem.ru/information6_3.html

An uncommon catalog of original and interesting electrical-engineering programs
http://www.tonnesoftware.com/index.html

TransistorAmp v1.1 - Design your own bipolar transistor amplifier quick and easy
http://en.transistoramp.de/

Полезни програмки:

Fritz Dellsperger
https://www.fritz.dellsperger.net/index.html

Analog Filter Wizard
https://tools.analog.com/ru/filterwizard/

Bri's world, electronics, programming and more
http://www.aaabbb.de/index_en.php#elektronik

http://www.aaabbb.de/JNumberTableMaker/ ... ker_en.php
PWM and function table calculation