TESORO GOLDEN SABRE

[metaldetector107]

TGSL

Dea Qiaozhi MAX Ivco
please how to measure RX frequency without capa and coil calculation
i mean with digital multimeter which has got frequency meter as well
thanks

[Qiaozhi]

Hi Ivconic,

Is this it? -> http://www.bikudo.com/product_search...capacitor.html

You said you had seen these in old VCRs, but I thought super capacitors were a relatively new innovation.

[Unregistered]

hi

please dear max,ivconic,qiazoni ,simonbaker

Can some one tell what i am doing here?

[aft_72005]

Hi Ivconic,

Is this it? -> http://www.bikudo.com/product_search...capacitor.html

You said you had seen these in old VCRs, but I thought super capacitors were a relatively new innovation.

Hi Qiozhi
It isn’t new innovation.
Best regards.

[Qiaozhi]

please dear max,ivconic,qiazoni ,simonbaker

Can some one tell what i am doing here?

I don't know!
I give up ... what are you doing here?

[Max]

I use hte PWB design attached in the first message of this thread. The bipolar capacitors are constructed of two 10u electrolytics in series, minus poles connected together.

The current consumption is 60mA. Is that correct?

There are 20mV ripple at 700kHz on the +8V rail, riding on 20mV ripple at the transmitter's frequency. How clean did you get that?

I have tried bypassing the 8V regulators in/output with 100n and the same for the PNP transistor's emitter of the negative voltage generator. No help.

I disconnected the 470n cap from pin 1 of the amp, that didn't help. Disconneting the 100k resistor from pin 3 did nelp a bit. I have a feeling, that the power rails should be cleaned before trying anything else. I can find ripple everywhere in the device, just can't find the source. Could the ripple be born somewhere else and it jsut get's amplified by the amp in question?

Andy
I have tried bypassing the

Hi,
the 60mA you read are a bit high but , depending on op amps you use, could be ok.
If you notice 130mA consumption when no sound there's a problem for sure, and you probably burnt the op amp that likely self-oscillate.

The ripple amplification is unavoidable in such designs, so the strategy is to keep noise low from start, avoid ground loops, filter any sensitive power line/rail etc anything you can do to keep noise as low as possible is fine.

I suggest you try 100nF directly at op amp site, on pads of power rails of it, then to gnd rail. That will filter out many spurious noise from it... but also, if you use hi CMRR devices you'll be shielded enough from that problems.

The 700Khz ripple is anything but good, so try these strategies described above to make it vanish if you can. The original board is not perfect but has been realized by many people here, including me with success so, can't be the board design for itself but other factors like e.g. rosin from solder wire etc you must clean it very well with e.g. isopropilic alcol or similar stuff (solvents).

Also, the voltage regulator can be a source of that noises... if have different ones try another and look for differences, could help too.

Kind regards,
Max

[Qiaozhi]

Hi Qiozhi
It isn’t new innovation.
Best regards.

It seems you are correct. I read somewhere that it was accidentally invented in the 1950s.

I guess I never realised that these small memory backup devices were actually supercapacitors.

There's some info here -> http://e-articles.info/e/a/title/Adv...upercapacitor/
that describes it as a cross between a normal capacitor and a battery.

[ivconic]

Yes Quiaozhi, that's the component! I have almost identical here by me.
Acts indeed like real capacitor!
So, i was thinking to wire it up at TGSL and observe behavior on scope. First i would like to wire it up at chopper output. Usually it produces -6.2V +/- 0.5V. So.... hopefully this special capacitor will further stabilize and filter negative rail at TGSL. Will try and see later..
Also, it would be good to wire it up to TX supply also.
Need to be checked.

[ivconic]

Quiaozhi many thanks for that link!!! Wow! Excellent explanation! Thanks much!

"...The most common supercapacitor applications are memory backup and standby power. In some special applications, the supercapacitor can be used as a direct replacement of the electrochemical battery. Additional uses are filtering and smoothing of pulsed load currents. A supercapacitor can, for example, improve the current handling of a battery. During low load current, the battery charges the supercapacitor. The stored energy then kicks in when a high load current is requested. This enhances the battery's performance, prolongs the runtime and even extends the longevity of the battery..."

So...this just justify my previous presumtion! It will turn that my question is not stupid at all!

[simonbaker]

Now is my turn to ask funny question;
have you ever noticed that capacitor-look-like component, usually present in older VCR's? Small component, exactly capacitor look, usually labeled as 0.47F (!!!!) 5V or 6V? Meaning actually 47 000 uF !!! Small...smaller than capacitors we are using mostly here.
So.. i took one recently and wired it parallel with one led diode and ps. Switched on ps and second after switched off. Led diode shined (diming down) for 2 minutes after!!!!!
So...actually it is capacitor. Hell of capacitor! Excellent to stabilize some voltage. So...here is my funny question:
How about, if we use that component(s) in TGSL? On very few places, especially on TX and eventually at chopper output (reversed, respecting polarities there)....ha?!
I asume, it will take a bit of time to charge fully from accu. So, after switching on, detector will be ready to operate after few seconds...
I never had any experiences before with this kind of capacitors....but shure this look like having some potentials to be used here...
I am very interested in your opinion..

I had same reaction when I saw it here and I had to buy it: http://www.goldmine-elec-products.co....asp?dept=1028

I know it must be good for something, just haven't figured out what yet.

It would be good for something needing sudden large current draw, like a camera flash. TGSL is pretty steady current. Maybe better for PI detectors. I tried bigger capacitors on TGSL negative supply to try to get rid of voltage spikes, but didn't help - they are too fast, smaller caps work better. Can't seem to improve on TGSL....

I think also might be good for micro-power projects, like solar powered radio beacon, etc.

Very intriguing -- we need separate thread somewhere with competition for most interesting application of this cap.

I'm for it...!

Regards,

-SB

[Max]

Yes Quiaozhi, that's the component! I have almost identical here by me.
Acts indeed like real capacitor!
So, i was thinking to wire it up at TGSL and observe behavior on scope. First i would like to wire it up at chopper output. Usually it produces -6.2V +/- 0.5V. So.... hopefully this special capacitor will further stabilize and filter negative rail at TGSL. Will try and see later..
Also, it would be good to wire it up to TX supply also.
Need to be checked.

Hi,
I think it's a good idea... cause will give enormous filtering effect!

Must find some old VCR...

Kind regards,
Max

[simonbaker]

Dea Qiaozhi MAX Ivco
please how to measure RX frequency without capa and coil calculation
i mean with digital multimeter which has got frequency meter as well
thanks

By RX frequency, I assume you mean RX coil-capacitor resonant frequency.

You need to get a signal generator which can make different frequency sine waves.

You need to connect the output of the signal generator to the RX coil (which is parallel to the capacitor) -- put a 100 ohm resistor in series with the signal generator output also.

If your multimeter can measure AC voltage up to 20000 Hz, you can use it. Otherwise, you need to use an oscilloscope.

Measure the voltage across the RX coil and slowly vary the signal generator frequency from 10000 Hz to 20000 Hz. When the voltage is highest, that is your RX resonant frequency.

Regards,

-SB

[Qiaozhi]

So...this just justify my previous presumtion! It will turn that my question is not stupid at all!

You never ask stupid questions.

[Ultimate_Haze]

I have try with cable that ivconic show for Eldorado.Much better stability.I now its not the right one but its best that I can find.
Also do you remember what molzar say.On the original setup coil wirement is diferent!I will try to show with pictures.
With 32ohm small speaker and last mode very stabile and loud sound.
Thanks

[ivconic]

I had same reaction when I saw it here and I had to buy it: http://www.goldmine-elec-products.co....asp?dept=1028

I know it must be good for something, just haven't figured out what yet.

It would be good for something needing sudden large current draw, like a camera flash. TGSL is pretty steady current. Maybe better for PI detectors. I tried bigger capacitors on TGSL negative supply to try to get rid of voltage spikes, but didn't help - they are too fast, smaller caps work better. Can't seem to improve on TGSL....

I think also might be good for micro-power projects, like solar powered radio beacon, etc.

Very intriguing -- we need separate thread somewhere with competition for most interesting application of this cap.

I'm for it...!

Regards,

-SB

Actually, i was thinking to experiment with more complex filtering;
super cap and small choke.
Now, job is to accuratelly calculate choke for this filter... we have 3.5-7kHz (approx) spikes there.. So choke must cover that bandpass.
Hmmm.... i would not be offended much if somebody help here with choke calculations..!