Another simple DC protection

hugobross · 25th September 2003, 01:30 PM

Hi all,

just read an article in a magazine about a simple DC protection...
it looks like in the picture.
any comments welcome...

Best regards,

HB.

poulkirk · 25th September 2003, 01:39 PM

Just too simple

What is there to stop it "Protecting" on legitimate AC Audio Signals

JOE DIRT® · 25th September 2003, 01:43 PM

hb...... optocouplers are used for isolation from the load and its a common practice in alot of designs
I use triac output devices for switching line voltage all the time to separate small signal devices from the load

DIRT®

hugobross · 25th September 2003, 01:43 PM

oooops a 'not shown' cap across the inputs of the rectifier...
it must be a LPF doh!!!

millwood · 25th September 2003, 01:45 PM

what about using an opamp integrator?

or maybe a 555?

X.G. · 25th September 2003, 02:41 PM

I think it is not better than the ordinary circuit.

because it's point of protect voltage is higher.

millwood · 25th September 2003, 03:18 PM

Quote:

Originally posted by X.G.
I think it is not better than the ordinary circuit.

I don't think the original circuitry will work as it will act on high a/c signals as well.

X.G. · 25th September 2003, 03:48 PM

Quote:

Originally posted by millwood
I don't think the original circuitry will work as it will act on high a/c signals as well.

I agree with you for a/c signals.

but in my experience,the PHOTO device work in several milliamperes.so i think above.

li_gangyi · 28th September 2003, 09:32 AM

And I though the AC music signal will be rectified to DC and the opto-isolator will trip...causing the relay to cut off...so izzit a protector??

kevin gilmore · 28th September 2003, 12:52 PM

As drawn this circuit will trigger for any dc or ac level that
exceeds +/- 2.1 volts with a time constant based on the
1k and 100uf cap.

25th September 2003, 01:39 PM	#2
poulkirk diyAudio Member Join Date: Aug 2003 Location: Western Australia	Just too simple What is there to stop it "Protecting" on legitimate AC Audio Signals __________________ Poul Kirk

28th September 2003, 09:32 AM	#9
li_gangyi diyAudio Member Join Date: Jun 2003 Location: Woodlands Circle	And I though the AC music signal will be rectified to DC and the opto-isolator will trip...causing the relay to cut off...so izzit a protector?? __________________ Kids in the back seat cause accidents...Accidents in the back seat cause kids...

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
simple loudspeaker protection needed	Flavio88	Multi-Way	0	11th January 2007 11:34 PM
A simple speaker protection circuit	Russ White	Parts	38	11th December 2006 01:39 PM
speaker protection (OR) overload protection	myanmar	Solid State	7	13th July 2006 08:21 AM
My first simple mains conditioner/surge protection:	maxlorenz	Parts	29	7th January 2006 05:53 PM
simple super-tweeter protection circuit	Macdude443	Multi-Way	3	22nd December 2004 05:16 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

25th September 2003, 01:43 PM	#3
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	hb...... optocouplers are used for isolation from the load and its a common practice in alot of designs I use triac output devices for switching line voltage all the time to separate small signal devices from the load DIRT®

25th September 2003, 01:43 PM	#4
hugobross diyAudio Member Join Date: Jun 2001 Location: Flanders, Belgium	oooops a 'not shown' cap across the inputs of the rectifier... it must be a LPF doh!!!

25th September 2003, 01:45 PM	#5
millwood Account Disabled Join Date: Apr 2003 Location: US	what about using an opamp integrator? or maybe a 555?

25th September 2003, 02:41 PM	#6
X.G. diyAudio Member Join Date: Sep 2003 Location: GuangDong China	I think it is not better than the ordinary circuit. because it's point of protect voltage is higher.

28th September 2003, 12:52 PM	#10
kevin gilmore diyAudio Member Join Date: May 2002 Location: wheeling illinois	As drawn this circuit will trigger for any dc or ac level that exceeds +/- 2.1 volts with a time constant based on the 1k and 100uf cap.