electronic flap for mosquito and fly.

[david753]

I am doing a research in electronic flap for mosquito and fly.
But, I was confused in this circuit.
Please refer to http://user52.starbeta.org/others/flap-e.doc
What is the role of transformer(left side have 2 sets) in circuit?
Does it(2 sets in left side of Transform) influence(reaction) each other?
Does anyone can analyze it?<p>David

[dacflyer]

the circuit looks to me like a step-up transformer type of circuit and the secondary side has rectifiers to further boost voltage..
i have something like this... the transformers primary..i kind of made that part of the circuit,,made my own primary coil wrapped around a flyback transformer... i use the HI-V anode to test suspect neon...i do not have to connect to the neon just get near it...if it glows then its ok,,, if not... time to fix it

[cato]

What the heck is an electronic flap for mosquito and fly?<p>The left side of the circuit is an oscillator. When the switch is first closed power supply voltage turns on the transistor. As current flows through the transistor it also flows through the lower coil of the left side of the transformer. The phasing of the coils is such that the current in the lower coil induces an opposing current in the upper coil. This tends to reduce the current in the base of the transistor and so reduces the current in the emitter circuit. Therefore the current in the lower coil is also reduced. This reduces the opposing current in the upper coil and the transistor is again turn on, once again increasing the current in the lower coil, and so on... In short, the upper coil provides the feedback that causes the oscillator to oscillate. <p>Is that clear?<p>[ January 17, 2004: Message edited by: cato ]</p>

[dacflyer]

the gadget is like a portable bug zapper..rather then them fly into it,, you swing it past them,and zapp !

[david753]

I was confused in this transform.
I try to measure the value of inductance in transform.
I got 306uH, 22uH, 1.06H respectively.
But, I caculate the ratio of voltage depend on sqart(L1/L2) formulation.
It is fail, the measurement of result didn't correspond to the result from formula.
Refer to,
http://user52.starbeta.org/others/flap-e.doc
For example, in left side of transform, input 5 Vp-p in upper side, get 1.68Vp-p in down side.
But, If Input 5Vp-p in down side, I get 2.24Vp-p
in upper side. It is not reasonable!!!

[Edd]

David:
I get from your English verbal nuances that you possibly might be from Taiwan ?
Also just guessing that this is a commercial unit that you are curious about and evaluating ? I have not seen one in the U.S. Seems like it might be useful, as compared to a conventional fly swatter where you have to wait for the fly or mosquito to land before hitting them. This way you could use it continually in a sweeping net fashion….unless/until some cadavers stick and short out its alternating terminal HV gridwork.
Looks like the power oscillator transistor is configured in the emitter follower mode in its coupling to the power transformers primary winding. With its secondary HV feed to a quadrupler circuit to feed your zappers HV gridwork.<p>On your <<It is not reasonable!!! >> reasoning when you were swapping drive between the two primary coils and not getting the expected results:
I suspicion your thinking was of the two windings being adjacent and on the core. In this case I think you will find the primary winding at the core proper, then the HV winding and then the feedback winding that serves the base being on the outside of
the transformer. This is more commonly used where there is initially a heavier load imposed by the secondary power winding and then a decreased requirement.(Like power supplies , capacitor charging, photoflash supplies, CD ignition, etc.)<p>Upon initial power-up there is a coupling between the two primary windings with the circuit running at a lower frequency (20khz) and then a gradual shifting to a higher frequency as the loading decreases with the caps charging up and tapering off in their power requirements. The HV voltage winding being between the two primary windings affords different degrees of inter-coupling in accordance to its loaded condition.<p>With the data you have ,but with some data not given , seems like the final DC across the C5 and C6 .012ufd cer caps should be in the order of ~6500 VDC. Any chance the voltage ratings of the caps were marked on them ?<p>73's de Edd
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[MrAl]

Hello there david,<p>In addition to the other good posts i'd like to add the following...<p>
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by david753:

But, If Input 5Vp-p in down side, I get 2.24Vp-p
in upper side. It is not reasonable!!!<hr></blockquote><p>
Then dont do that!!!!!!!!!!
<p>The lower input side of the transformer was probably designed
for a max peak of about 1.6 or so, so when you try to drive it
with 2.5v peak there is a good chance you saturate the core
due to it's flux being driven too high. If this is really
happening if you check the waveform you'll see flat topping
or other distortion with a sine wave input. If it's designed
for 1.25v peak an you drive it with 2.5v peak your pushing
the flux up to twice it's intended value.
Notice that when you drive the upper input winding you do
get 'reasonable' results.<p>Solution? Drive the lower winding with less test voltage,
say 1v peak (2v peak to peak) and repeat the test.
Let us know what happens if you do this test <p>Also, with a 3v battery i get 1.2v peak input (lower winding)
and about 250v peak output, providing a final 1000vdc output.<p>Take care,
Al