In my newist build I have a 15VAC tap in the PT. I drew up this schematic to power 3 relays, channel switch, boost and mid boost. I'll use 12V relays and 1000uF caps, 50 ohm series resistor.
Will this work?
thx
Edit:
Relay schematic?
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Relay schematic?
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Last edited by Bob-I on Wed Jun 28, 2006 4:26 pm, edited 2 times in total.
Re: Relay schematic?
Sure, it will work. The actual amps also have a cap at the output of the voltage regulator. 4700uF is cool if you have the real estate for that size caps, otherwise 1000uF is what the master himself used. With the regulator in there, 1000uF has proven to be plenty as per my experience.Bob-I wrote:In my newist build I have a 15VAC tap in the PT. I drew up this schematic to power 3 relays, channel switch, boost and mid boost. I'll use 12V relays and a 4700uF cap.
Will this work?
thx
Gil
Re: Relay schematic?
Excellent, thx. I'll pick up a pair of 1000uF caps and put it together.ayan wrote:Sure, it will work. The actual amps also have a cap at the output of the voltage regulator. 4700uF is cool if you have the real estate for that size caps, otherwise 1000uF is what the master himself used. With the regulator in there, 1000uF has proven to be plenty as per my experience.Bob-I wrote:In my newist build I have a 15VAC tap in the PT. I drew up this schematic to power 3 relays, channel switch, boost and mid boost. I'll use 12V relays and a 4700uF cap.
Will this work?
thx
Gil
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skyboltone
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voltage doubler on the recto filament winding
I'm intending to use the 5 volt rectifier filament winding in a voltage doubler scheme. There's five amps there to work with. It should be fine too. I think. I did notice in one of the pictures under review these days that the master used a separate filament transformer to do the job.
Dan
Dan
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Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Re: Relay schematic?
Does the 12v regulator need to be grounded?
Re: Relay schematic?
Also 15vac rectified would be 21v, do you need a resistor to shed the
extra voltage for 12v relays?
extra voltage for 12v relays?
Re: Relay schematic?
Bob
it seems to me that diodes are wired in the reverse direction!
teo
it seems to me that diodes are wired in the reverse direction!
teo
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glasman
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Re: Relay schematic?
On your first question,tonelab2 wrote:Also 15vac rectified would be 21v, do you need a resistor to shed the
extra voltage for 12v relays?
THe center is normally grounded, but you can play games with diodes in the ground leg to raise the voltage a little.
The regulators (7812) are good for 35 volts on the input. So the resistor is corrected.
Also someone asked about the bridge, it is correct.
Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification
www.glaswerks.com
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification
www.glaswerks.com
Re: Relay schematic?
Actually the 12V block is a regulator. It should be good for up to 35V.tonelab2 wrote:Also 15vac rectified would be 21v, do you need a resistor to shed the
extra voltage for 12v relays?
Re: Relay schematic?
I was wondering about that. Can anyone confirm the correct orientation of the diodes for click reduction?llemtt wrote:Bob
it seems to me that diodes are wired in the reverse direction!
teo
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glasman
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Re: Relay schematic?
Bob-I wrote:I was wondering about that. Can anyone confirm the correct orientation of the diodes for click reduction?llemtt wrote:Bob
it seems to me that diodes are wired in the reverse direction!
teo
The diodes across the relays are backwards. They are forward biased as shown. They need to be reverse bias with the Cathodes on the 12V rail.
Gary
Located in the St Croix River Valley- Afton, MN
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification
www.glaswerks.com
About 5 miles south of I-94
aka K0GWA, K0 Glas Werks Amplification
www.glaswerks.com
Re: Relay schematic?
Ahhh... thxglasman wrote: The diodes across the relays are backwards. They are forward biased as shown. They need to be reverse bias with the Cathodes on the 12V rail.
Gary
Re: Relay schematic?
With the 15V rms, you'll have ~21v dc before the regulator, so it will have to dissipate 9 Volts times the total relay current, in your case about 120 ma?(my relays are ~40 ma each) which is over a watt, even with a good heat sink, that might get pretty darn hot.
You might think about adding a series resistor in front of the regulator to drop some of the extra volts you have. (~50 ohm 2W)
You might think about adding a series resistor in front of the regulator to drop some of the extra volts you have. (~50 ohm 2W)
Re: Relay schematic?
Thx, I was wondering about the dissipation.sgp wrote:With the 15V rms, you'll have ~21v dc before the regulator, so it will have to dissipate 9 Volts times the total relay current, in your case about 120 ma?(my relays are ~40 ma each) which is over a watt, even with a good heat sink, that might get pretty darn hot.
You might think about adding a series resistor in front of the regulator to drop some of the extra volts you have. (~50 ohm 2W)
Re: Relay schematic?
Bob-I, the rectifier and relay diodes are drawn correctly.
Gil concurred it would, also Gary pointed out the Cathodes should be connected to the +12 vdc rail, and are as shown. You want them reversed biased with the relay ON and at relay turn off, when the collapsing magnetic field induces a reverse voltage across the coil, the diodes are forward biased suppressing the shot noise. Sorry if this seems to overstate anything.
Gil concurred it would, also Gary pointed out the Cathodes should be connected to the +12 vdc rail, and are as shown. You want them reversed biased with the relay ON and at relay turn off, when the collapsing magnetic field induces a reverse voltage across the coil, the diodes are forward biased suppressing the shot noise. Sorry if this seems to overstate anything.