by w2aew @ youtube.com:
Today’s “Back to Basics” tutorial topic – why flyback or snubber diodes are used around relay coils when switched or controlled by low power electronics. We’ll talk about how and why dangerously high voltages can be generated from the collapse of the stored magnetic energy in the coil when they’re switched off, and how the diode can protect the low power electronics from being damaged by these high voltages. Some voltage and current measurements are made on an actual circuit to see the real-world effects.
Why diodes are used around relay coils - [Link]
by Barry Harvey @ edn.com:
We analog designers take great pains to make our amplifiers stable when we design them, but there are many situations that cause them to oscillate in the real world. Various types of loads can make them sing. Improperly designed feedback networks can cause instability. Insufficient supply bypassing can offend. Finally, inputs and outputs can oscillate by themselves as one-port systems. This article will address common causes of oscillation and their remedies.
Does your op amp oscillate? - [Link]
A good beginner app note (PDF) from NXP on protecting ICs from ESD.
Integrated circuits are sensitive to electrostatic discharge (a sudden and short-time flow of currents) and electromagnetic fields (at which they can be source or victim of both of it). This application note shall be understood as an introductive basic description of what electrostatic discharge is, how sensitive devices can be protected against electrostatic discharges, what electromagnetic compatibility means and how electromagnetic sensitivity can be tested.
App note: ESD and EMC sensitivity of IC - [Link]
by w2aew @ yoututbe.com
Op amp gain-BW product and slew rate limiting are defined, discussed and demonstrated on the bench. This discussion applies to the majority of general purpose op amps on the market – as most op amps are internally compensated with a single dominant pole. High speed op amps, unconditionally stable op amps, non-unity gain stable op amps, high power opamps, etc. may not follow these characteristics because they are often compensated differently in their design. An LM358N is used for the example circuit. Other popular op amps like the LM741, etc. will behave in a similar way. Sometimes the slew rate limit of a device will be the dominant factor in determining the bandwidth, and other times the gain-bandwidth product will determine the resulting frequency response. The video demonstrates why this happens.
Basics of Op Amp Gain Bandwidth Product and Slew Rate Limit - [Link]
How Ferrite Beads Work – EMI Suppression - [Link]
by Einar Abell:
This Design Idea demonstrates a simple way to generate a multiphase clock signal, the frequency of which can be varied with minimal change in phase shift(s).
The phase shift of the second output can be tuned from near zero to 180° without affecting the frequency. The basic circuit uses a minimum of parts: one cap, two resistors, plus two Schmitt triggers.
Add phases to simple RC oscillator - [Link]
Open Analog is an organization dedicated to exciting makers about analog hardware. We make popular ICs into transistor level kits!
The first Open Source analog IC kit from Open Analog has been created, assembled, and verified. We call it the SevenFortyFun and it is a transistor level op amp kit. You can finally get the chance to understand whats going on inside those ICs! Now we need your help to proto the next revision (I gotta eat somehow!). This Kickstarter campaign is to raise money in order to print the first batch of PCBs and order parts for production volume.
741 Op-Amp Kit - [Link]
Warren Young of Tangentsoft writes:
Experienced audio DIYers are familiar with monolithic linear regulators like the 78xx series and the LM317. Here’s a simplified block diagram of a standard linear regulator, from National Semiconductor’s Application Note 1148
Let’s see… We have an op-amp, a couple of transistors, a voltage reference, and a few resistors. Can we build a linear regulator from these individual components? Yes, we can!
Op-Amp based linear regulators - [Link]
App note(PDF) on schottky rectifiers from Microsemi.
Schottky rectifiers have been used for over 25 years in the power supply industry. The primary advantages are very low forward voltage drop and switching speed that approach zero time making them ideal for output stages. This latter feature has also stimulated their additional use in very high frequency applications including very low power involving signal and switching diode requirements of less than 100 picoseconds.
App note: Introduction to schottky rectifiers - [Link]
Analysis of the bipolar transistor amplifier at low-frequency is relatively easy, and several calculators exist online that do a good job. For high-frequency operation, there are fewer references available. For my projects, I like to build a reference spreadhseet where everything is in one place. This allows me more flexibility in optimizing the circuit, and is much faster than simulating with LTSpice or similar package. Furthermore, constructing such a tool is a great way of gaining more insight into how the circuit works, and how each of the parameters affects performance.
Common-Emitter and Common-Collector Transistor Amplifier Calculator for High-frequency Operation - [Link]