Video Tutorial on the Design and Characterization of Class-B and AB Amplifiers - Page 1
Forum section: electronics / projects

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 04, 2013, 05:25:04 pm
content: In this episode Shahriar continues his investigation of discrete Bipolar amplifier design. The advantages and disadvantages of Class-A amplifiers are explained. The conceptual schematic of a Class-B amplifier is presented which leads to the introduction of Class-AB amplifier circuit to overcome the ‘dead-zone’ impairment of a push-pull Class-B design. To further improve the Class-AB amplifier and lower its input impedance, a final Class-A followed by Class-AB amplifier is presented The component parameters are calculated and the schematics is explained in detail. All circuits are then implemented on a breadboard and tested both in the time domain and frequency domain. All schematics can be downloaded from The Signal Path website.The video can be viewed here: [40 Minutes]http://thesignalpath.com/blogs/2013/02/04/tutorial-on-the-design-and-characterization-of-class-b-and-ab-amplifiers/More videos:http://www.TheSignalPath.com

author: firewalker
author_rank: Super Contributor
timestamp: February 04, 2013, 08:00:08 pm
content: Really good!I believe that it would be less confusing to a beginner if you had included biasing resistors when explaining AB. Maybe it would be nice an addendum with designing amplifiers without symmetrical supply.And if am not wrong a diode is reversed.Alexander.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 04, 2013, 08:10:16 pm
content: Quote from: firewalker on February 04, 2013, 08:00:08 pmYou are absolutely correct about the diode. I have added a note to the video and corrected the schematics which are available to download. I also added a note that the diodes require a small bias current to maintain their junction voltages. I am very happy to see that people watch the videos carefully to catch small mistakes like this. Thank you!

author: MikeK
author_rank: Super Contributor
timestamp: February 04, 2013, 11:04:03 pm
content: Thanks, Shahriar. I only just started watching it. But doesn't the Class A amplifier also need bias resistors? It's confusing to hear that it's always on, but see no reason for it. As drawn it's only on when with an input signal.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 05, 2013, 01:24:29 am
content: Quote from: MikeK on February 04, 2013, 11:04:03 pmYes, it does need biasing. Sometimes when talking about small-signal operation, the biasing circuitry is not shown. The full schematic of the Class-A amplifier was shown in one of my previous videos.

author: ConKbot
author_rank: Super Contributor
timestamp: February 06, 2013, 05:26:20 pm
content: Nice work I enjoyed the video, It made me feel like going to the elliot sound products site and nosy though some amplifier schematics. The application of current sources/sinks in amps could be interesting, but a vid on long tail pairs and current source/sinks might be a bit too specific.

author: Hugoneus
author_rank: Frequent Contributor
timestamp: February 07, 2013, 04:28:09 am
content: Based on some suggestions I have updated the schematics on the website. Cheers