DC Circuit questions - Tilted Forum Project Discussion Community

Herk · 04-04-2008, 07:34 AM

I hate that I went to school for this less than 10 years ago, and it is already all Greek to me.

Any way the circuit currently is:

So basically this buzzer is going off the entire time the door is open. What I'd like to do is make it do that the buzzer goes off for a set time and then shuts off until the next time the door opens. This could probably be done easily with a 555 timer, but I don't want to go that route. I want to know how to do it with simple components only. No ICs.

I think it can probably be done with a transistor, a capacitor, and a few resistors. Maybe a diode as well. Then changing the values would change the duration of tone.

Anybody have the know-how to draw up this circuit. I love testing my brain power while preserving plasticity.

JamesB · 04-04-2008, 12:53 PM

What you are describing sounds like an LRC circuit. I also suspect you will want a latching relay for your application.

Scorpion23 · 04-09-2008, 04:35 PM

I think that by the time you make the circuit out of standard components you'd be close to emulating the purpose of a 555. Is there a particular reason you're shying away from the IC route?

But anyway, I'll have to check my circuit books for a simple one. I made an LED flasher years ago that alternated between two different color LEDs. I'm pretty sure it let a charge build up in the transistor until it was enough to open the gate. I'll see if I can find it.

Also, I know it's more convention than anything else in a low-voltage circuit, but the switch should be between the buzzer and + terminal.

ASU2003 · 04-09-2008, 04:36 PM

The simplest way is exactly the circuit you have, except that when the door is fully closed, it will be off and when it is fully open it will be off. You have to come up with some track a wire can ride on or some piece of metal on top of the door that will make contact when opening, but not when shut or fully open.

I don't know, that is my idea on the simple way to do it.

That is kind of strange we replied to a 5 day old thread at the same time...

Scorpion23 · 04-09-2008, 04:39 PM

And went back to edit at the same time as well, haha.

Herk · 04-15-2008, 06:23 AM

I apologize for not following up here, but I thought I should post my conclusion in case anybody else was interested. I asked on an electronics forum, as well. I got an answer that was precisely what I was looking for.

The reason I avoided the IC was merely to test my brain.

Here is the link. http://www.dutchforce.com/~eforum/in...dpost&p=154443

04-04-2008, 07:34 AM	#1 (permalink)
Herk Insane Location: Kansas City, MO	DC Circuit questions I hate that I went to school for this less than 10 years ago, and it is already all Greek to me. Any way the circuit currently is: So basically this buzzer is going off the entire time the door is open. What I'd like to do is make it do that the buzzer goes off for a set time and then shuts off until the next time the door opens. This could probably be done easily with a 555 timer, but I don't want to go that route. I want to know how to do it with simple components only. No ICs. I think it can probably be done with a transistor, a capacitor, and a few resistors. Maybe a diode as well. Then changing the values would change the duration of tone. Anybody have the know-how to draw up this circuit. I love testing my brain power while preserving plasticity. __________________ -Blind faith runs into things!-

04-04-2008, 12:53 PM	#2 (permalink)
JamesB Insane Location: Ottawa	What you are describing sounds like an LRC circuit. I also suspect you will want a latching relay for your application. __________________ -- apt-get install spare_time --

04-09-2008, 04:35 PM	#3 (permalink)
Scorpion23 Psycho	I think that by the time you make the circuit out of standard components you'd be close to emulating the purpose of a 555. Is there a particular reason you're shying away from the IC route? But anyway, I'll have to check my circuit books for a simple one. I made an LED flasher years ago that alternated between two different color LEDs. I'm pretty sure it let a charge build up in the transistor until it was enough to open the gate. I'll see if I can find it. Also, I know it's more convention than anything else in a low-voltage circuit, but the switch should be between the buzzer and + terminal. __________________ "Empirically observed covariation is a necessary but not sufficient condition for causality" - Edward Tufte Last edited by Scorpion23; 04-09-2008 at 04:38 PM..

04-09-2008, 04:36 PM	#4 (permalink)
ASU2003 immoral minority Location: Back in Ohio	The simplest way is exactly the circuit you have, except that when the door is fully closed, it will be off and when it is fully open it will be off. You have to come up with some track a wire can ride on or some piece of metal on top of the door that will make contact when opening, but not when shut or fully open. I don't know, that is my idea on the simple way to do it. That is kind of strange we replied to a 5 day old thread at the same time... Last edited by ASU2003; 04-09-2008 at 04:37 PM.. Reason: Automerged Doublepost

04-09-2008, 04:39 PM	#5 (permalink)
Scorpion23 Psycho	And went back to edit at the same time as well, haha. __________________ "Empirically observed covariation is a necessary but not sufficient condition for causality" - Edward Tufte

04-15-2008, 06:23 AM	#6 (permalink)
Herk Insane Location: Kansas City, MO	I apologize for not following up here, but I thought I should post my conclusion in case anybody else was interested. I asked on an electronics forum, as well. I got an answer that was precisely what I was looking for. The reason I avoided the IC was merely to test my brain. Here is the link. http://www.dutchforce.com/~eforum/in...dpost&p=154443 __________________ -Blind faith runs into things!-