Relay and LED Circuit...Nooby Needs Help

[PRR]

> are they fast enough?

A good question.

An ideal inductor has an infinite rise time. No real inductor does, and infinite anything gives simulators problems. So I simmed a reasonable perfect inductance with 720 ohms added in series, approximately your relay. The external rise-time (what the diode sees) is not incredibly fast.

I get peak diode current equal to the relay current, peak diode dissipation 0.090 Watts (it approaches but does not reach both 12V and 17mA), and average dissipation like 0.006W for hundreds of clacks per second (faster than the relay, far faster than your finger).

Not fast. In this case, not high current or high voltage.

It would be hard to find a diode which would NOT work.

(Obvious no-go diodes: transisor B-E junction won't block >7V, small vacuum-diode won't pass 17mA at low voltage.)

 

[Phrazemaster]

So when does the electronics book come out? (or has it already?) Seriously you've got a lot to offer. Thank-you so much for gracing me and all of us with your time, and for simulating aspects of the relay I'm using.

So any diode will work well here, my understanding. I do over think things, and in my rush to understand all of this I read up on a lot of stuff that was saying, it has to be fast with a large current rating and low forward voltage drop, etc. I had found one at digikey but of course it was expensive, and as you say you want to try to build with easily attainable preferably cheap parts for design and production considerations. I changed my design to use the 1N4007's you suggested.

Thanks!

 

[Phrazemaster]

OK, I wanted to post a proposed circuit for a board I'd like to make. Just focus on the Phase aspect (the first relay) and see if I've correctly translated the schematic that PRR simplified for me. I'll repost it in the next post, since I can't figure out how to do multiple attachment.s

Not shown is the actual switch, just the board that would accept its inputs.

Thanks any thoughts,

Mike

 

[Phrazemaster]

Here's the schematic. The crossing lines from the switch are not connections.