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]
A primer app note(PDF) on silicon transient voltage suppressors by Microsemi.
Silicon transient voltage suppressors (TVSs) are clamping devices that limit voltage spikes by low impedance avalanche breakdown of a rugged silicon pn jucntion. They are used to protect sensitive components from electrical overstress such as that caused by induced lightning, inductive load switching and electrostatic discharge.
App note: What is a silicon transient voltage suppressor and how does it work - [Link]
by Peter Demchenko @ edn.com:
Low-current switching regulator ICs often use a Darlington as the output switch. The power conversion efficiency in this case can be improved with the help of only two cheap components. To make this possible, the chip should have a separate pin for the collector of the driver transistor Q1 (Figure 1). At startup, D1 forms a path for the collector current of Q1. Later, D1 and C1 comprise a current-additive rectifier which enhances the collector voltage and current of Q1, hence reducing voltage drop on the closed switch Q2.
Improve efficiency of low-cost switcher - [Link]
Energy is transmitted in different ways and one of these ways is electricity. It can appear in many forms and through various phenomena such as lightening or electromagnetic induction, and can be used in transport, electrical appliances, and in the residential and industrial sector, to name but a few examples. Physical magnitudes are derived from electricity such as the electric field, current, and electric potential. The latter two are measured in amps and volts respectively.
In order to measure the previous magnitudes and many others, ingenious devices have been developed, called multimeters, which are the perfect example of the high integrity and versatility of the most modern measuring instruments. They are powerful devices, small in size, but large in their ability to detect and solve electrical failures, measure a large variety of parameters such as current, voltage, capacity, resistance, and they are also equipped with additional functions which allow them to measure temperature, continuity, frequency, carry out diode tests or perform as an oscilloscope. Many multimeters have a USB port and have wireless transfer capacity (Bluetooth), which means that the measurement results can be sent to a PC or computer for later analysis. In addition, many of them are designed in such a way that their screen is removable, so that they can operate in difficult to access areas. Read the rest of this entry »
by Henrik’s Blog @ hforsten.com:
In my previous post I wrote about a circuit that would change it’s output depending on what was the spice simulations DC sweep range. Today I investigated the circuit a little and I was able to remove lots of components that didn’t affect the bug and this is the resulting circuit.
Metastable transistor circuit - [Link]
An application note from Texas Instruments, A single-supply Op-Amp circuit collection (PDF!):
There have been many excellent collections of op-amp circuits in the past, but all of them focus exclusively on split-supply circuits. Many times, the designer who has to operate a circuit from a single supply does not know how to do the conversion.
Single-supply operation requires a little more care than split-supply circuits. The designer should read and understand this introductory material.
A single-supply Op-Amp circuit collection - [Link]
By Dean Segovis @ makezine.com:
A transistor is an electrical component that functions, most basically, as a switch — in principle not so different from a light switch. Instead of a physical movement, however, a transistor is controlled by a flow of electricity. And unlike your basic light switch, a transistor can be on, off, or somewhere in between.
Non-Contact Voltage Detector - [Link]