Help with 12V to 5V setup, having powering issues.

**soundman98** · 10-17-2011, 05:23 PM

you'll need a transistor-- look around the M2 section. there are a couple of threads that talk about a solution to the low output of the anti-thump pin(where it won't have enough juice to turn on some amps)-- that circuit should be the exact thing you'll need.

**HiJackZX1** · 10-17-2011, 05:38 PM

Well the PAC has enough juice to turn on the relay, the problem is that its a pulse device so its turning off the relay off and on really fast. I figured that if I put a capacitor, then it would store the pulse and release it as constant, or do I have things wrong?

**soundman98** · 10-17-2011, 05:44 PM

ah...

i was going to start on the explanation of how to make it work, but honestly, it is much more work then it is worth. you'd need a diode to prevent the voltage from going back into the PAC, a resistor to keep the voltage going slowly through the relay, a capacitor to store the charge, and a least a weekend to figure out what values of resistor and capacitor are the correct ones for this application...

just get one of the devices i linked to before-- that will solve the problem and give you a larger adjustment window if the 2 seconds isn't enough..

**OldSpark** · 10-17-2011, 05:49 PM

Thru a diode to a cap to the PAC....

Don'tcha hate products without specs (TR4) like input current & impedance, time delays etc.
(Hence why so many DIY with web circuits.)

**HiJackZX1** · 10-17-2011, 06:02 PM

Originally Posted by OldSpark

Thru a diode to a cap to the PAC....

Don'tcha hate products without specs (TR4) like input current & impedance, time delays etc.
(Hence why so many DIY with web circuits.)

A diode to a cap to the PAC, or did you mean the relay?

Well I know the time delay is 2 seconds on the PAC.

**HiJackZX1** · 10-17-2011, 06:13 PM

Is this what I am doing?

**soundman98** · 10-17-2011, 06:16 PM

yes, it would need to be on the output side of the PAC.

though, oldspark will need to confirm, i thought that a resistor would be needed in something like this to prevent a smaller-sized capacitor from discharging too fast between pulses..

**HiJackZX1** · 10-17-2011, 06:41 PM

What is the purpose of the diode though? To keep the current from going backwards?

**OldSpark** · 10-17-2011, 09:11 PM

Originally Posted by some stupid OldFart

Thru a diode to a cap to the PAC....

Sorry - my bad - I meant "Thru a diode to a cap to the device...." (ie, relay).

The point being the diode.
As per HiJack's diagram, from PAC TR4 thru diode to cap & relay.
The PAC charges the cap (hopefully without stressing the PAC's output).
When charged enough, the relay turns on (ie, when voltage across the cap exceeds the relay "turn on" voltage.

When the PAC turns off, the diode prevents the cap discharging thru the PAC. It must discharge thru the relay coil etc.

The 10k fixed resistor is not needed - it is only there to discharge the cap.
But the (say) 60R to 250R (R=Ohm) coil resistance "swamps" the 10k (eg, parallel R = (10k x 250)/(10k+250) = 243R = close to the 250R)
- ie, the cap discharges through the lowest resistance (250) much quicker than the 10,000 resistor.

If only audio buffs could fit a diode between their supply (battery, alternator) and the cap and amplifier.... (LOL!)