(editor’s note: Intrigued by the problem? Have a question or another solution? Then click the “Read more” link and follow the conversation on EDAboard.com or log in to EDAboard and participate in the analog forum threads.) Flyback source and magnetic air gap – I was studying dc-dc converters because I want to do a flyback voltage […]
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Are your op amps pumped?
I was recently thinking about the issues surrounding rail to rail input opamps and the problems of making them low distortion – a problem I have had to overcome when designing integrated circuits for instrumentation applications. Some rail to rail opamps use two input stages – one using NMOS input transistors, the other using PMOS […]
Basics of bandpass filters
Filters will allow some signals to pass through while blocking others. A bandpass (a.k.a. band-pass) filter allows signals of a certain frequency range (“a band of frequencies”) to pass through the filter as-is. (This range of accepted frequencies is called the passband. The size or range of the passband is called the bandwidth.) With a […]
Making sense of thermocouples and interfaces, part 2
Part 1 of this FAQ looked at the basics of thermocouples, where and why they are used, and some basic implementation issues; this part explores interface issues, cold junction compensation, and linearization. What are the requirements for thermocouple interface electronics? The thermocouple voltage is relatively small, so long leads between the thermocouple and the electronic front-end […]
Making sense of thermocouples and interfaces, part 1
Temperature is the most frequently measured real-world variable, and despite its age, thermocouples are still among the most-used temperature sensors. They are used in test and measurement equipment, instrumentation, and even in standard home ovens due to their low cost, reliability, simplicity, and ability to measure into hundreds of degrees. What is a thermocouple and […]
Unity gain amplifier or voltage follower in a voltage divider
A voltage follower is also known as a unity gain amplifier, a voltage buffer, or an isolation amplifier. In a voltage follower circuit, the output voltage is equal to the input voltage; thus, it has a gain of one (unity) and does not amplify the incoming signal. The voltage follower does not need any external […]
How do RFID tags and reader antennas work?
By Anil Pandey RFID — Radio-Frequency Identification — provides a unique identifier for that object and just as a bar code or magnetic strip the RFID device must be scanned to retrieve the identifying information. An RFID system has three parts: A scanning antenna A transceiver with a decoder to interpret the data A transponder […]
Top analog threads on EDAboard.com – April
(editor’s note: Intrigued by the problem? Have a question or another solution? Then click the “Read more” link and follow the conversation on EDAboard.com or log in to EDAboard and participate in the analog forum threads.) Long distance cell phone detector – I found these schematics on a circuit diagram website. After building it many […]
Passive sensors and active sensors: What are they?
“Passives” in general within the electronics community are devices that do not drive or transmit power or signals. Passive Sensors do not control electricity directly and do not require external power sources to accomplish control of an electrical signal. Examples of passive components are resistors (R), capacitors (C), inductors (L), transformers, antennas, potentiometers (variable resistors), […]
Mutual inductance & transformers: when EMF becomes EMI
Mutual inductance is superbly demonstrated in a transformer. Transformers are made up of two wire coils placed close each other such that current running in one coil can induce a voltage in the other coil without the coils touching. Power can be transferred without a metal connection with a transformer, and transformers can be […]