I use this super-simple circuit (with an additional winding) to experiment with magamps and it seems to work correctly:
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But I found a weird circuit in this 1961 patent:
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What advandages does the second generator have? It contains coils connected to the emitters and collectors, with no obvious through-base feedback. I have never seen such an arrangement before -- what's that?
On a sunny day (Mon, 23 Nov 2015 13:23:22 +0100) it happened Piotr Wyderski wrote in :
It is normal pushpull, with feedback in the emitters. Dunno about 'Royer'. But I think it will switch on saturation? So non-linear, probably. At some point the current in the coils is limited by base resistor Rb, so from that POV it is a current source, but not sure, it is easy to test if you have a ring core and 2 transistors and a meter or so wire? For the principle it does not make any difference NPN or PNP or Si or Ge.
That is a Royer then. The idea of the Royer is the to use the saturable transformer to switch the transformer (so it will always run at max flux swing)
A better idea is the Royer-Jensen, which has a current sense transformer to act as the saturating element, so the main transformer is working below saturation and thus has potential lower losses
As far as I can see, both are Royers. The second one has added a constant current output
On a sunny day (Mon, 23 Nov 2015 15:00:15 +0100) it happened Piotr Wyderski wrote in :
In that article they use variants that make you think the author calls everything a 'Royer' Maybe he came from down under and believes in anthropogenic glowballworming (I see Baxandall mentioned).
Once you talk about a PWM drive it is a totally different beast IMO. For example the frequency is then set by the driver's oscillator, not by the core.
For this reason I have deliberate (?) amnesia if somebody wants to put a name of YAO oscillator, as _anything_ with a feedback gain of > 1 and the right phase will oscillate, so then there would be an infinite number of 'topologies', and there are.
We do not have that many words in all languages combined.
Yes a scope is a good thing to have. Best is an analog one, those do not lie.
CRTs may become extremely valuable collector items.
[standard blocking oscillator, two transistors, saturating xformer]
A disadvantage is that it'll be hard to start. The only advantage I see, is that the emitter windings operate at high current into a low-impedance emitter, rather than into a high-impedance base, so the turns count on those windings is low. It's easier to wind the transformer.
Your circuit, which 'seems to work', relies on EB breakdown of one switch, in order for the other switch to conduct. It also has no base current limit. Drawn with a grounded feedback centertap, the avalanche can be avoided and feedback turns reduced. Add the resistor in the ground tap and the base current can be limited to account for a required overdrive to account for intended circuit loading.
The second circuit employs the high Veb ratings of germanium power transistors to shift a proportion of the load to the emitter winding. A typical 12 volt circuit might have 3x as many turns in the emitter winding, as in the collector winding.
Both circuits depend on main core saturation for determination of switching period. Feedback windings that supply only base currents are obviously easier to fool around with.
Not really, It has two centre-tapped widings same as Royer (variant with a single bias resistor), just in this patent one of the cenre-tapped coils is drawn as two coils. (typical patent obfuscation)
?? the transistors in a royer are common emitter, the base terminal is low impedance, the turns count for the bases only generates about 5V (any more risks avalanching B-E).
You do get fewer turns total wih this "Geyger" layput though, so less wasted space and no fragile fine wires needed the base.
Might have been interesting if it concerned the actual thread title as well, but should probably have been 'AC source for magamp'......or 'self-oscillating inverter'.
Do ignorance and interest have inverse relationships?
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