How this circuit like?

[mikebg]

can you tell more about yourself? how old are you? are you communist Chinese or capitalistic Taiwanese?

After long time in production with flat legs (as shown below), transistor KT315 is now produced in case TO92:
http://www.transistor.by/i/pdf/kt315.pdf

In the past century, 2N3904 was the most widely used cheap transistor for general purpose in the United States.
The same can be said of the transistor KT315, widely used in the ex country Sovjet Union or USSR. Lithuania, Belarus and Russia participated in this "union" (Bulgaria was a secret participant :-). Now there is no the country Sovjet Union, but in Belarus remains production of KT315.

What means nickname "KT315"? Is it nostalgia that feels Anatolij Kutovoj for communism (when there was no unemployment in the Lithuania) or nostalgia for nonexisting powerful Soviet Army (where Anatolij had to fulfill his military service about 30 years ago)л

Not! The alias KT is simply a school nickname comming from Kutovoj.
Dear KT315, the letter "T" is not from of yours first name because it is in the middle of "AnaTolij". Ask your ex classmates to tell you that KT comes from your last name, but this is absolutely not important. Important is what participants in this world forum feel for a gentlemen known here as KT315.

I have feeling that Anatolij is an excellent expert in this hobby, sharing his knowledge almost with all.

But why "almost"?

Because there are several participants who do not feel the same as me.
If I was drunk and I had written (in such a condition) something similar to posting #2, once sober I'd be ashamed. I'd apologize to Yhl and ask the Administrator to delete that posting.

As Anatolij not guilty, that was born in the communist country Sovjet Union, upposed to serve in the Red Army, and Yhl not guilty, that is born Chinese.

However, everyone (even drunk) is to blame for his behavior to others.

[mikebg]

However, if you use CD4046, no need of mixer, because this IC has an output noted as "phase pulses".

When you use a PLL circuit for reference oscillator, no need of knobs for adjustment. These knobs are noted as "jemné" (fine) and "hrubé" (coarse) in postings #1 and #8 above. The circuit in #8 below also needs such adjustments with C1 (fine) and with core of L1 (coarse).

As shown below, the circuit of Macario has only a switch S for fast setting at beat frequency zero, when you adjust R1. However S and R1 are not buttons for operator; they are inside control box.

[mikebg]

Yhl, CD4013 contains two D-type Flip-Flops. The flip-flop makes level change of outptuts Q and Q when both inputs (R and S) are zero as shown in the truth table below. Its operation as mixer in BFO MDs is represented by oscillogrames in postings #1 and # 5.

[yhl]

Why do all the mixer with the CD4013?


Why do all the mixer with the CD4013?This can transform CD4013 mixing it?

[mikebg]

Thank you MIKEBG. Hope this is a good circuit. I need you to help build.

Yhl, for me a good circuit operates in a principle that can not be improved.

You found a Bulgarian site for beginning builders. It shows old primitive operating circuit diagrams. However you're not beginner because are a participant in our forum. Our participants already know the shortcomings of the conventional BFO type circuits and methods for their improvement. As you follow postings for BFO on the forum this year, already know that the circuit diagram, you choose for building, has at least 4 shortcomings that can easy be improved:

1. Search oscillator operates with sensing head type MONOCOIL. For better sensitivity, the search oscillator should use separate TX and RX coils placed almost in induction balance. Rev. Thomas Scarborough reinvented and renamed the circuit of Leslie Hoggard as "CCO metal detector", but this is not whole detector, only the sensing part.

2. Search oscillator excites environment and targets with wery low TX power. For better sensitivity we need a powerful oscillator builded with an audio IC for example LM386, which drives TX coil with its internal noise as if it is a loudspeaker. Leslie Hoggard also uses LM386 in project HOUNDOG. Even Rev. Thomas uses it in an of his projects for CCO.

3. Search oscillator operates at too high frequency (about 100kHz), which causes large GND signal. To reduce GND signal, we should use two RX coils connected as TWIN LOOP and connect large capacitances for LC circuits to tune them for lower resonance frequncy, for example 14kHz.

4. Since reference oscillator can't compensate instability of search oscillator, the operator must often use both buttons for coarse and fine adjusting. However we know that no need of such buttons. We can use a PLL IC as reference oscillator, for example CD4046. Such IC uses Macario in his project "Discriminative metal detector". The BFO principle with PLL reference oscillator operates as very sensitive motion type detector.

Here is a MD circuit with CD4046 from above Bulgarian site, but it operates at high frequency. The circuit of Macario is much better.

[yhl]

Thank you MIKEBG.

Thank you MIKEBG. Hope this is a good circuit. I need you to help build
I have a site inside a circuit
http://www.pchelar-probvaisambg.com/..._68_spisak.htm

[mikebg]

Yhl, when you post large images, try to reduce their width to 1024 pixels if the heigth is not large (or their heigth to 640 pixels if the width is not large). I use for Resize/Resample of images the free program IrfanView. It has an option "Preserve Aspect Ratio" and you easy reduce only width or only height.
Compare my posting below with your posting above. Participants in this forum can see in my posting the whole circuit diagram without scrolling.

[kt315]

fascists, you mean hazi here probably, gave people the work places, got up the economic, developed the industry. now I have not the work! I have been retired without my wish! so think what you write about.

[mikebg]

KT315, does it matter what is yhl's age and party? The important thing is that he wants to be like us, to learn something, to receive information. How would you feel if they ask if you are a retired Red Army officer and if you have membership in a fascist party? Yhl has already 76 postings in this forum. Note that recently he writes in more understandable English. Your questions are not offensive to refuse him to start new threads in this forum. Hang on as a modern European, rather than fascist in 30-ies years of last century.

Yhl, your circuit is a BFO MD. The reference oscillator operates at 4th or 5th harmonic of search oscillator. Frequencies are for example 455kHz and 80 ... 120kHz. The original article of this project was published in German magazine "Funkschau" May 1984. The circuit above is extracted from a reprint made in Chech magazine "Amatérské Radio" April 1990 page 126.
The oscillogrames represent:
1. Reference oscillator output,
2. Search oscillator output,
3. Output of IOз, pin 1,
4. Voltage across headphones.
Headphones should be piezo or high impedance.

[kt315]

can you tell more about yourself? how old are you? are you communist Chinese or capitalistic Taiwanese?

[yhl]