Changing the current of a battery - Page 1
Forum section: electronics / projects

author: Joseph Aragon
author_rank: Newbie
timestamp: December 25, 2013, 09:09:36 pm
content: Hi there! I'm Jospeh and I'm new in this forum. First of all, I'd like to explain that I'm not an expert in this field, I'm just amateur. I've designed this circuit:What I'm trying to do is to obtain the same output frequency just by feeding the TRIAC with direct current and the gates with alternating current (provided by domestic network), and to get the same output frequency as the one of the domestic network.Thank you in advance!P.S.: I'm sorry if there's something not clear; my English vocabulary in this field is quite limited

author: Rerouter
author_rank: Super Contributor
timestamp: December 25, 2013, 09:34:03 pm
content: i am no expert with triacs either, but I'm pretty certain you will want to swap the gate drive of one triac on either side, to me it seems this would just short positive and negative on both halves of the cycle,

author: TerraHertz
author_rank: Super Contributor
timestamp: December 26, 2013, 06:25:18 am
content: Hi Joseph.This is going to sound like a put-down, but seriously it's not meant to. It's meant to save your life.I'm afraid your circuit and comments reveal your understanding of Triacs isn't yet adequate. It's *so* bad, that I think your general knowledge of electronics is also likely quite limited - yet here you are proposing to experiment with circuits directly connected to the mains. This is *very* dangerous for you.There are so many things wrong with your drawing and idea, that my best advice, seriously, is that you should experiment with low voltage circuits only. For a while yet, anyway. Please, get yourself a bench power supply, with outputs of (say) zero to 25V, and use that.If you *must* try using TRIACs, get an isolation step down transformer, with at most 50 VAC output, and use that output for driving the Triacs.Start with just one Triac, a simple resistive load, and a means for triggering the Triac.Do you have a scope?

author: BravoV
author_rank: Super Contributor
timestamp: December 26, 2013, 06:44:26 am
content: Quote from: TerraHertz on December 26, 2013, 06:25:18 amAssuming your guess about his electronics knowledge level is true, then this remark is even more dangerous, poking a probe at mains unknowingly about the scope capabilities and lack of the experience and understanding in electronics is life threatening activity.Just becareful when playing with mains related stuff.

author: TerraHertz
author_rank: Super Contributor
timestamp: December 26, 2013, 07:49:23 am
content: Quote from: BravoV on December 26, 2013, 06:44:26 amYes indeed. Especially if someone (cough) has floated the scope earth.If he said 'yes' I was going to go into that, and suggest some experiments to try using a LV isolated triac circuit. NOT that circuit he drew.

author: vk6zgo
author_rank: Super Contributor
timestamp: December 26, 2013, 10:10:36 am
content: Looking at his schematic,it seems he is trying to create a 230v AC output,using a 230vDCinput by switching alternate triacs on & off with an external AC source,so as to alternately reverse the connection between the +ve & -ve inputs & the output terminals.I'm not really a triac guru,but it seems to me,that even if it works ,it is unlikely that the output will be in any way a sinewave.

author: oldway
author_rank: Super Contributor
timestamp: December 26, 2013, 01:06:39 pm
content: A new Mc Murray-Bedford inverter without need of forced commutation ..Next step: Philosopher's stone...Please read something about triacs before posting ...

author: Unknown
author_rank: Unknown
timestamp: December 28, 2013, 01:19:18 am
content: To be alittlebit more helpful (but only a little)...At the moment, it seem you don't know enough about electronics to know what you don't know. There's a number of problems with your design, not the least of which is a fundamental misunderstanding of how triacs work.I'd recommend that before you build even a low-voltage prototype you take a look at circuit simulation software (e.g. LTSpice), teach yourself enough to enter your schematic & connect the virtual instruments, & play with a simulation model of your circuit. That'll let you see what's happening at various points (e.g. the voltage & waveform at the output) under a variety of input conditions (e.g. AC, single pulse, etc).If you do that, hopefully you'll see that it won't work and - more to the point - have some ideawhyit can't work.

author: oldway
author_rank: Super Contributor
timestamp: December 28, 2013, 03:31:42 pm
content: And the next time, post such newbies schematics in theBeginnerstopic.Look for: fast turn off scr, forced commutation, Mc Murray Bedfort inverter, ...on Internet.