The frequency response of a BJT or MOSFET can be found using nearly the exact same process, with the only variations being caused by a single resistor and simple naming conventions that differ between the two devices. Before we start let’s think a little bit about what we’re doing: Our goal is going to be [...]
Tags: Basic Electrical Engineering Concepts, BJT, Cadence, Electrical Engineering, Electrical Engineering Concepts, Engineer, MOSFET, Parallel Resistance Formula, pole, PSPICE, transistor
The following is an explanation of symbol conventions , voltage polarities and current directions for npn and pnp BJTs. The goal is to help understand these characteristics but not on the physical level of electrons and holes. The following figure shows practical operation of each BJT in the active mode. npn or pnp? When looking [...]
Tags: base, BJT, collector, Current, Electronics, emitter, npn, pnp, transistor, voltage
Basic BJT Equations: It is also important to know that can be modeled as . These equations are not very informative by themselves so a few examples are demonstrated below. In both examples we will assume is very large. What this means for our calculations is . Since we also assume that . Finding missing [...]
Tags: alpha, base, beta, bipolar, BJT, collector, Current, emitter, junction, npn, pnp, transistor, voltage
Sometimes it can be complicated understanding and calculating hole and electron concentrations. My intent in this article is to briefly, but thoroughly describe what the variables used in these calculations mean and how to use them. To begin I will introduce our variables: concentration of free electrons (donors) concentration of holes (acceptors) = number of [...]
Tags: acceptor, atom, calculate, concentration, donor, electron, hole, junction, n, n-p, n-type, p, p-n, p-type
This post is about amplifiers, how they work, and common applications. I will cover several operational amplifier configurations, and situations where each might be useful. This is part I of II for general discussion about amplifiers. Enjoy! Amplifiers Definition (for Bioinstrumentation): Circuit that makes a small signal, usually voltage but occasionally current or power, big [...]
Tags: Amp, Amplifier Saturation, Amplifier Schematic, Amplifiers, Bias Current, CMRR, Common-Mode, DC offset, Diff Amp, Difference Amp, Differential Amp, Frequency Dependance, Gain, Input Impedance, Instrumentation Amp, Operational Amplifier, Output Impedance, Saturation, Wheatstone Bridge
