12V latch circuit - help to modify or design, please

G

Gus

Guest
Hi all - this problem has been driving me nuts for a week now!

I need to switch some 240V garden lights from several different
locations. Each of the locations has 2 conductor bell wire in place
buried underground so I can't easily run additional wires.

So I thought I'd use a 12V relay to switch the 240V supply, and use a
flip-flop type circuit so I could turn it on or off using momentary
contact push buttons at the various locations.

I found this circuit here, which seems perfect for the job :
www.nalanda.nitc.ac.in/industry/appnotes/Zetex/dn27.pdf

But the problem is that the circuit requires two transistors that I
can't find in Australia. I have tried buying them off-shore but nobody
will ship goods worth less than about $100.00.

Can someone look at the circuit and suggest equivalent transistors
that I can find locally?

Thanks in advance

Gus
 
Thanks for the transistor quivalents - you solved my problem in one
second.

As for the diode, I recognize it is to deal with back EMF from the
relay coil (found this on the net) and I realize it's not critical
that I find the exact one. I was planning to use 1N914 from DSE (Part
No. Z3120)

Again thanks for the help. I'll post a follow up when I've put it all
together.

Gus


On Fri, 29 Aug 2003 15:14:55 GMT, KLR <kreed@bigpond.net.au> wrote:

On Fri, 29 Aug 2003 22:29:16 +1000, Gus <gazman@pobox.com> wrote:

Hi all - this problem has been driving me nuts for a week now!

I need to switch some 240V garden lights from several different
locations. Each of the locations has 2 conductor bell wire in place
buried underground so I can't easily run additional wires.

So I thought I'd use a 12V relay to switch the 240V supply, and use a
flip-flop type circuit so I could turn it on or off using momentary
contact push buttons at the various locations.

I found this circuit here, which seems perfect for the job :
www.nalanda.nitc.ac.in/industry/appnotes/Zetex/dn27.pdf

But the problem is that the circuit requires two transistors that I
can't find in Australia. I have tried buying them off-shore but nobody
will ship goods worth less than about $100.00.

Can someone look at the circuit and suggest equivalent transistors
that I can find locally?

Thanks in advance

Gus

Out of interest - where did you get an IN4000 Diode ? I cant say I
can recall ever having seen listed anywhere any type smaller than an
in4001.
(ps - you can use any diode from in4001 - in4007 instead)


ZTX 300 I would try a BC 547

ztx550 try using a BC 557 these will probably work fine.

For driving anything bigger than a small cradle relay or solid state
relay I would consider replacing both of the Ztx550 with a single BD
682

As I recall - This being a darlington with a about a 4a rating it
would work well. Also has a hole in the package so you can bolt
attatch it to a heatsink if you will be pulling that much current for
any length of time

Have used these in the past for driving small solenoids and lamps with
good results. DSE has them (or did when I last looked) so they
shouldnt be too hard to find.
Click to expand...
 
I would use a power diode (and not a signal diode like 1N914) try a 1N4001
or similar one in the 1N400x series .


"Gus" <gazman@pobox.com> wrote in message
news:hpevkvo4g5apmqb4us2carse6hpoa0rn19@4ax.com...
: Thanks for the transistor quivalents - you solved my problem in one
: second.
:
: As for the diode, I recognize it is to deal with back EMF from the
: relay coil (found this on the net) and I realize it's not critical
: that I find the exact one. I was planning to use 1N914 from DSE (Part
: No. Z3120)
:
: Again thanks for the help. I'll post a follow up when I've put it all
: together.
:
: Gus
:
:
: On Fri, 29 Aug 2003 15:14:55 GMT, KLR <kreed@bigpond.net.au> wrote:
:
: >On Fri, 29 Aug 2003 22:29:16 +1000, Gus <gazman@pobox.com> wrote:
: >
: >>Hi all - this problem has been driving me nuts for a week now!
: >>
: >>I need to switch some 240V garden lights from several different
: >>locations. Each of the locations has 2 conductor bell wire in place
: >>buried underground so I can't easily run additional wires.
: >>
: >>So I thought I'd use a 12V relay to switch the 240V supply, and use a
: >>flip-flop type circuit so I could turn it on or off using momentary
: >>contact push buttons at the various locations.
: >>
: >>I found this circuit here, which seems perfect for the job :
: >>www.nalanda.nitc.ac.in/industry/appnotes/Zetex/dn27.pdf
: >>
: >>But the problem is that the circuit requires two transistors that I
: >>can't find in Australia. I have tried buying them off-shore but nobody
: >>will ship goods worth less than about $100.00.
: >>
: >>Can someone look at the circuit and suggest equivalent transistors
: >>that I can find locally?
: >>
: >>Thanks in advance
: >>
: >>Gus
: >>
: >Out of interest - where did you get an IN4000 Diode ? I cant say I
: >can recall ever having seen listed anywhere any type smaller than an
: >in4001.
: >(ps - you can use any diode from in4001 - in4007 instead)
: >
: >
: >ZTX 300 I would try a BC 547
: >
: >ztx550 try using a BC 557 these will probably work fine.
: >
: >For driving anything bigger than a small cradle relay or solid state
: >relay I would consider replacing both of the Ztx550 with a single BD
: >682
: >
: >As I recall - This being a darlington with a about a 4a rating it
: >would work well. Also has a hole in the package so you can bolt
: >attatch it to a heatsink if you will be pulling that much current for
: >any length of time
: >
: >Have used these in the past for driving small solenoids and lamps with
: >good results. DSE has them (or did when I last looked) so they
: >shouldnt be too hard to find.
: >
: >
:
 
that's what I said an hour ago !!!


"KLR" <kreed@bigpond.net.au> wrote in message
news:qbpvkvot7fg1on1v29scuoscp1gco240nk@4ax.com...
: On Sat, 30 Aug 2003 06:45:16 +1000, Gus <gazman@pobox.com> wrote:
:
: >Thanks for the transistor quivalents - you solved my problem in one
: >second.
: >
: >As for the diode, I recognize it is to deal with back EMF from the
: >relay coil (found this on the net) and I realize it's not critical
: >that I find the exact one. I was planning to use 1N914 from DSE (Part
: >No. Z3120)
: >
: The IN914 is a small signal diode and is lesser rated than a power
: diode.
:
: While it probably will work fine in this circuit where a small relay
: is being driven - I would feel a lot more comfortable with a power
: diode such as an 1n4002- in4007 doing this job
:
:
: >Again thanks for the help. I'll post a follow up when I've put it all
: >together.
: >
: >Gus
: >
: >
: >On Fri, 29 Aug 2003 15:14:55 GMT, KLR <kreed@bigpond.net.au> wrote:
: >
: >>On Fri, 29 Aug 2003 22:29:16 +1000, Gus <gazman@pobox.com> wrote:
: >>
: >>>Hi all - this problem has been driving me nuts for a week now!
: >>>
: >>>I need to switch some 240V garden lights from several different
: >>>locations. Each of the locations has 2 conductor bell wire in place
: >>>buried underground so I can't easily run additional wires.
: >>>
: >>>So I thought I'd use a 12V relay to switch the 240V supply, and use a
: >>>flip-flop type circuit so I could turn it on or off using momentary
: >>>contact push buttons at the various locations.
: >>>
: >>>I found this circuit here, which seems perfect for the job :
: >>>www.nalanda.nitc.ac.in/industry/appnotes/Zetex/dn27.pdf
: >>>
: >>>But the problem is that the circuit requires two transistors that I
: >>>can't find in Australia. I have tried buying them off-shore but nobody
: >>>will ship goods worth less than about $100.00.
: >>>
: >>>Can someone look at the circuit and suggest equivalent transistors
: >>>that I can find locally?
: >>>
: >>>Thanks in advance
: >>>
: >>>Gus
: >>>
: >>Out of interest - where did you get an IN4000 Diode ? I cant say I
: >>can recall ever having seen listed anywhere any type smaller than an
: >>in4001.
: >>(ps - you can use any diode from in4001 - in4007 instead)
: >>
: >>
: >>ZTX 300 I would try a BC 547
: >>
: >>ztx550 try using a BC 557 these will probably work fine.
: >>
: >>For driving anything bigger than a small cradle relay or solid state
: >>relay I would consider replacing both of the Ztx550 with a single BD
: >>682
: >>
: >>As I recall - This being a darlington with a about a 4a rating it
: >>would work well. Also has a hole in the package so you can bolt
: >>attatch it to a heatsink if you will be pulling that much current for
: >>any length of time
: >>
: >>Have used these in the past for driving small solenoids and lamps with
: >>good results. DSE has them (or did when I last looked) so they
: >>shouldnt be too hard to find.
: >>
: >>
:
 
On Sat, 30 Aug 2003 13:31:45 +1200, "Eric" <some1@clear.net.nz> wrote:

that's what I said an hour ago !!!

Great minds think alike obviously ? :)
Click to expand...

"KLR" <kreed@bigpond.net.au> wrote in message
news:qbpvkvot7fg1on1v29scuoscp1gco240nk@4ax.com...
: On Sat, 30 Aug 2003 06:45:16 +1000, Gus <gazman@pobox.com> wrote:
:
: >Thanks for the transistor quivalents - you solved my problem in one
: >second.
:
: >As for the diode, I recognize it is to deal with back EMF from the
: >relay coil (found this on the net) and I realize it's not critical
: >that I find the exact one. I was planning to use 1N914 from DSE (Part
: >No. Z3120)
:
: The IN914 is a small signal diode and is lesser rated than a power
: diode.
:
: While it probably will work fine in this circuit where a small relay
: is being driven - I would feel a lot more comfortable with a power
: diode such as an 1n4002- in4007 doing this job
:
:
: >Again thanks for the help. I'll post a follow up when I've put it all
: >together.
:
: >Gus
:
:
: >On Fri, 29 Aug 2003 15:14:55 GMT, KLR <kreed@bigpond.net.au> wrote:
:
: >>On Fri, 29 Aug 2003 22:29:16 +1000, Gus <gazman@pobox.com> wrote:
:
: >>>Hi all - this problem has been driving me nuts for a week now!
:
: >>>I need to switch some 240V garden lights from several different
: >>>locations. Each of the locations has 2 conductor bell wire in place
: >>>buried underground so I can't easily run additional wires.
:
: >>>So I thought I'd use a 12V relay to switch the 240V supply, and use a
: >>>flip-flop type circuit so I could turn it on or off using momentary
: >>>contact push buttons at the various locations.
:
: >>>I found this circuit here, which seems perfect for the job :
: >>>www.nalanda.nitc.ac.in/industry/appnotes/Zetex/dn27.pdf
:
: >>>But the problem is that the circuit requires two transistors that I
: >>>can't find in Australia. I have tried buying them off-shore but nobody
: >>>will ship goods worth less than about $100.00.
:
: >>>Can someone look at the circuit and suggest equivalent transistors
: >>>that I can find locally?
:
: >>>Thanks in advance
:
: >>>Gus
:
: >>Out of interest - where did you get an IN4000 Diode ? I cant say I
: >>can recall ever having seen listed anywhere any type smaller than an
: >>in4001.
: >>(ps - you can use any diode from in4001 - in4007 instead)
:
:
: >>ZTX 300 I would try a BC 547
:
: >>ztx550 try using a BC 557 these will probably work fine.
:
: >>For driving anything bigger than a small cradle relay or solid state
: >>relay I would consider replacing both of the Ztx550 with a single BD
: >>682
:
: >>As I recall - This being a darlington with a about a 4a rating it
: >>would work well. Also has a hole in the package so you can bolt
: >>attatch it to a heatsink if you will be pulling that much current for
: >>any length of time
:
: >>Have used these in the past for driving small solenoids and lamps with
: >>good results. DSE has them (or did when I last looked) so they
: >>shouldnt be too hard to find.
:
:
:
Click to expand...
 
OK. Thanks again, I have some 1N4004 that I was using on the circuit
to protect against accidental mis-connection of the power supply but
I'll use the same one across the relay also.

Gus
 
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