Maker Pro
Maker Pro

What's wrong with circuit?

Colin Mitchell

Aug 31, 2014
1,416
Joined
Aug 31, 2014
Messages
1,416
"A 1N4007 diode is rated for 1000 V PRRV, peak repetitive reverse voltage. It is NOT NOT NOT a zener diode of any kind. "

Of course it is a 1,000v zener diode. What do you think it is??????

"In a circuit like this that has no external earth ground reference, it is NOT the case that the N wire (Neutral) "does not move at all"."

What do you think the neutral wire is?

Of course it does not move. It is connected to the earth and in many cases it is "generated" by a pipe hammered into the ground.

How can you draw a PNP as a typical NPN style.

The fact that the circuit is up-side down, no-one came along to analyse the circuit, and still haven't.
 

Colin Mitchell

Aug 31, 2014
1,416
Joined
Aug 31, 2014
Messages
1,416
You can't have 16.7v across the resistors and 12.7v across the 1k because the transistor is turned ON and all the leads are at the approx same potential.
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
You can't have 16.7v across the resistors and 12.7v across the 1k because the transistor is turned ON and all the leads are at the approx same potential.
Well, that's what my fluke meter tells me.
What I'm trying to figure out is why my triac is staying on. It's only supposed be on when the high frequency from Tx is applied.
I believe it's because the base is not negative enough to drive the transistor into full saturation.
Do you agree?
 

Colin Mitchell

Aug 31, 2014
1,416
Joined
Aug 31, 2014
Messages
1,416
"Well, that's what my fluke meter tells me."

It's a FLUKE they work at all.

You have to remember, when there is a high frequency in a circuit, these high impedance meters do not work at all.
A TV technician came to me 40 years ago and said there was positive on the grid of the 6CM5 valve via his new digital multimeter.
I used my cheap analogue meter and it was minus 35 volts.

His meter was picking up the horizontal scan frequency.
This is just one lesson you have learnt that has never been described in any text book or lecture . . because the teacher has never used a meter in his life.

You have not shown the transmitter and, as I have said, we know nothing about how the circuit works.
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
"Well, that's what my fluke meter tells me."

It's a FLUKE they work at all.

You have to remember, when there is a high frequency in a circuit, these high impedance meters do not work at all. .....
You have not shown the transmitter and, as I have said, we know nothing about how the circuit works.
I get you point but I'd hardly call Fluke an inferior brand.
No, there's no high frequency applied because the Tx circuit is not turned on.
So I don't think there's over 60hz on this circuit or perhaps a harmonic of it.

I can show the Tx circuit but I believe it works fine as I can hear the high frequency when I power it up. Regardless, the Rx circuit shouldn't be driving the triac without seeing the 18khz from the transmitter.

Here's the description of how it works.
http://danyk.cz/ovladani_sit_en.html
 

Colin Mitchell

Aug 31, 2014
1,416
Joined
Aug 31, 2014
Messages
1,416
You set the whole circuit up with an isolation transformer

IsolationTransformer.gif IsolationTransformer.jpg

Connect a 3 watt night-light as the load
Flipped-3.gif
Now short between base and emitter and the lamp should turn ON.

Now
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
You set the whole circuit up with an isolation transformer....

Now
Why? Do you suspected I'm picking up interference and the isolation Xformer will filter it out? (alas, I don't have one)

As I said, the triac is always on at this point.

Why would I want to short from base to emitter? Conversely It may be worth trying to short collector to emitter and see if the triac shuts off.

I'm away from the circuit right now but am trying to get my head around this.

So I can't do it "Now". Lol

Regards, John
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Ahh ha. It was an interference after all, as I believe Colin was hinting to.
I took the circuit home from work and all the little gremlins went away.
It works, but it's a bit too sensitive even with replacing the 220k bias resistor with a 180k. I think I need to add more filtering to the high pass filter also.

I'm grateful for everyone here who share their knowledge so freely.

Regards, John
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
John,
Others may be able to give a more educated answer but I am assuming the 33nF and 4K7 are the filter (in your 120v version). 15nF and 4K7 in the 240v version
I get ( using 1/2*pi*RC) around 2khz and with the original 15nF around 1Khz so I don't really see how it makes much difference.
Maybe I'm barking up the wrong tree ( done that before)
Good to see it "kind-of " works ...:)
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
RxCkt.jpg Thank you bluejets. The video says its 18khz. I think the high pass filter is comprised of the two 22n caps and the 1k on the left side.

I plan on having the transmitter triggered by a Pir motion sensor and will see if receiver portion works without any false trips.
I don't want it going off at 3am and freaking out the wife.

I've attached a picture of the 120v circuit for future reference.

Thanks again, very cool circuit.

Btw, I'll repost to let others know if it works 500ft away.
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
The video says its 18khz. I think the high pass filter is comprised of the two 22n caps and the 1k on the left side.

I looked up this circuit section, called a 2nd order high pass filter, and found this equation.(pic below)
Using the values I still only get around 2Khz.
 

Attachments

  • 2ndOrderFilter.jpg
    2ndOrderFilter.jpg
    3.4 KB · Views: 49
  • Filter.jpg
    Filter.jpg
    13.8 KB · Views: 45

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Ok, but I was thinking the 4k7 was only for limiting current to the 33n.
Examples of Rc filters seem to always have the cap in series followed by a resistor in parallel. Just using one stage 22n and 1k, I get 7.23khz. But don't know how the second cap in conjunction with the diode would be calculated.
For that matter, I wouldn't know what frequencies I would really need to block to mitigate false triggers.
Plus, I don't have a scope, frequency counter or spectrum analyzer.
It's still fun to expand my limited knowledge of electronics when I can.
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
To me it seems the 33nF and the 4K7 are across the mains so first filter section, 2nd section is the 22nF and the 1K............ just as shown in the last attachment.

I would imagine the other 22nF on the base is to block any DC component and just allow the signal to pass.
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Aww man! I'm bummed out.
I got the circuit working good inside the house, but it doesn't work outside at 400ft.

I will make sure I'm using transmitter and receiver on the same branch circuit cable but I doubt it will work.

I guess I need to add a second stage to the transmitter it more powerful.
 

Bluejets

Oct 5, 2014
6,901
Joined
Oct 5, 2014
Messages
6,901
Just out of curiosity, you originally mentioned the remote circuit was for lighting so was this switched on at the time.
I imagine it would need to be.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
There are all sits of signals and noise on the mains that could trigger this circuit. An isolation transformer would attenuate these somewhat. Long wires will act as antennae to pick up more interference :-(
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Just out of curiosity, you originally mentioned the remote circuit was for lighting so was this switched on at the time.
I imagine it would need to be.
No it wasn't switched on.
I've got the receiver portion driving a night light for testing purposes. I adjusted sensitivity pot just below the threshold where triac switches on, so it's as sensitive as it can be. Transmitter just doesn't seem to have enough wattage to work over long distances like that. I tried fiddling with the receiver frequency too, but to no avail.
 
Last edited:

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
There are all sits of signals and noise on the mains that could trigger this circuit. An isolation transformer would attenuate these somewhat. Long wires will act as antennae to pick up more interference :-(
Like I said, it works perfectly in the house.
it's not being falsely triggered.
I can plug tx circuit in any outlet and even about 100ft away and it switches on fine. But walking to end of my driveway about 400ft (120m) away and it doesn't work.
I have noticed transmitter works better when pot is adjusted to highest frequency output.
Perhaps I could try and adjust ohm values to get it higher, but my hunch is that it doesn't have enough wattage to work at these distances.
 
Last edited:

AnalogKid

Jun 10, 2015
2,884
Joined
Jun 10, 2015
Messages
2,884
"A 1N4007 diode is rated for 1000 V PRRV, peak repetitive reverse voltage. It is NOT NOT NOT a zener diode of any kind. "

Of course it is a 1,000v zener diode. What do you think it is??????
I think it is a rectifier. Yes, I am aware that a zener diode acts as a rectifier when forward biased, That does not mean that a simple rectifier can act as a zener diode when reverse biased. And by "act as a zener", I mean with a defined, stable zener voltage.

Please post a datasheet for a 1N4007, indicate where on the datasheet it is called a zener diode, or indicate where on the datasheet it lists the zener voltage and its tolerance.

ak
 

Tha fios agaibh

Aug 11, 2014
2,252
Joined
Aug 11, 2014
Messages
2,252
Would simply adding two more transistors in order to increase wattage from transmitter work?
 

Attachments

  • 1484539304717.jpg
    1484539304717.jpg
    148.3 KB · Views: 52
Top