## Comprehensive Relay Kickback Voltage Analysis

Relay is made up of two elements; the coil and the contact. The coil needs to be energized so that the contact will change state. For detailed analysis on how to drive the relay coil for it to energize read this. In this topic we will jump directly to relay kickback voltage analysis. As mentioned, relay has a coil. This coil

## Opto Coupler CTR Explanation

Opto coupler CTR explanation is not well elaborated by other authors and before I was also having hard time of understanding what is it. Current transfer ratio or commonly known as CTR is the ratio of the collector current to the forward current of an optocoupler. It is synonymous to a current gain of a bipolar junction transistor. If this is the first

## Designing MOSFET Switch – Comprehensive

MOSFET is not well discussed in the undergrads; much more how to designing MOSFET switch. MOSFET stands for metal oxide semiconductor field effect transistor. Actually it is easier than BJT if we are talking a switch circuit. Nowadays MOSFET is very popular in circuit designs. Such in automotive, power supply and general electronics as a low side and high side

## How to Analyze Optocoupler in Feedback System

One of the usual applications of optocoupler is to provide isolation between two ground reference. That is why it is often seen in power supply feedback circuit. How to analyze optocoupler in feedback system is to discussed in this article. Keep on reading below. How to analyze optocoupler in feedback system is not as difficult as you think. However, the lack

## How to Drive a Transistor into Hard Saturation

How to drive a transistor into hard saturation? In using a transistor to operate as a switch you must drive it into saturation. Saturation happens when the collector current cannot further increase despite there is base current increase. The saturation level of every transistor varies. The usual range is from 0.7V to ideally zero. For instance for a BC817-25 transistor,