Blocking Oscillator

Thread Starter

anditechnovire

Joined Dec 24, 2019
93
please am a beginner in electronics and am just getting to understand simple basic self oscillating circuit so i got stumbled in the so called one of the easiest self oscillating circuit,
"the blocking oscillator". The information I get in many website are so confusing and contradicting, even the diagrams, are different, so i don't know which one to trust.
So please can anyone come up with any geniue basic diagram of a blocking
oscillator with a good explanation to help me out, I'll really appreciate it.
 

Papabravo

Joined Feb 24, 2006
13,926
You might be so new to electronics that explanations of what is going on in an oscillator are beyond your ability to comprehend. You might be better served by looking at the required information in a more structured fashion. Which units of the textbook associated with this site have you completed? I would say that you to read and understand thoroughly the material in Vol I (DC circuits), Vol II (AC Circuits), and Vol III (Semiconductors) before you tackle Oscillators. You have to learn to crawl and walk before you try to run a marathon
 

ci139

Joined Jul 11, 2016
1,559
the blocking osc is not that easy . . . it's because the coupled inductor (a transformer) is quite a strange beast . . . it's because the transistor is quite a strange beast also

however a falstad simulation . . . if it helps anything

+ LT Spice -- the same stuff Blkg-Osc.png
 
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Thread Starter

anditechnovire

Joined Dec 24, 2019
93
No
You might be so new to electronics that explanations of what is going on in an oscillator are beyond your ability to comprehend. You might be better served by looking at the required information in a more structured fashion. Which units of the textbook associated with this site have you completed? I would say that you to read and understand thoroughly the material in Vol I (DC circuits), Vol II (AC Circuits), and Vol III (Semiconductors) before you tackle Oscillators. You have to learn to crawl and walk before you try to run a marathon
I understands you, but that's not really the case, I deeply understand the theory of using mosfet and transistors as switches. And also the concept of flyback systems, inductors and transformers. So if am being given a clear explanation, I hope I'll understand quickly.
 

ci139

Joined Jul 11, 2016
1,559
show the exact oscillator you need the description for . . . schematic or link to

otherwise . . . basically -- ↘↘ ••• the collector coil has rising current value thus the secondary (base winding) tries to compensate that change
about http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html
and generates current at the opposite direction (that is when the I -ry and II -ry are tied so that ones end meets the others beginning)
that opens the transistor more and more faster and faster (like a chain reaction)
, then when the system has no more power to force the primary's current more higher the secondary's current also fades
(which starts) closing the transistor .... and causes the primary's current also to fade . . . that in turn is get again compensated by the secondary
but this time the 2-ry coil tries to compensate the fading primary thus it sucks the current off the base of the NPN thus closing it completely at some point . . . which will cause the peak collector voltage spike -- that is induced by the stored but changing flux in the coil
when the flux fades (enough) the NPN starts opening again and pass current through the primary ••• ↖↖
the above is somewhat simplified description as you will find out when you need to dissect the case in as full detail as possible (the Ic and Ib will be oscillating before the NPN closes . . .)

the circuit can be modified to produce different wave shapes and pulse packets or made synchronous

as ... maybe this
 
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Papabravo

Joined Feb 24, 2006
13,926
No

I understands you, but that's not really the case, I deeply understand the theory of using mosfet and transistors as switches. And also the concept of flyback systems, inductors and transformers. So if am being given a clear explanation, I hope I'll understand quickly.
Sorry, that was not at all clear from your original post. It has been 53 years since I did that circuit in the lab as an undergraduate and I have not used it in a career that spanned half a century. It is dubious that I could do the explanation from memory since those notes are long gone. I did look for them to see if they might be helpful. Good Luck
 
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