This unit has some weird schematic oddities that are slightly perplexing. Is the first transistor acting like a regulator? Why is there a diode in series with the shunt switch instead of a resistor to prevent contact damage? You can hear the pop from the switch as it shunts the capacitor. The unit seems to work in the sense that it has a violet LED and electrified grid, but the circuitry is slightly weird.
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This scheme is not strange, but very thought out. The transistor opens when, the voltage on the LED becomes higher than on the batteries 1.2v+0.6v. And charges the capacitor on 56 kOhm in parallel with a resistor. Which provides displacement to the base of the generator transistor.
Nice one Clive… the wife has got one and I'm going to take ours apart to look
If I was designing such device with a big button to switch it off, I would totally use the switch to short the grill and discharge the high voltage part.
Maybe it’s weird because the designer didn’t really know what they were doing? Lol
i have 1 of these ,its never recharged useless
Clive, I am so very lucky to have one of these units. Never had any issues with it, It just stopped working in the last couple of days. I can only presume that the AAA battery has died due to insufficient charging over the winter. Can you tell me, if I replace the AAA battery with a "normal'" rechargeable battery, would it work and still be safe? OR am I just better to drop kick it and get a new one instead? Tar chuck!
I have recntly a need to zap the crap out of some bugs. Thus seeking the parts in needed. Can 2 usb chargers transformers be connected to dramatically increase the voltage before entering the capacisitor(s)? I seek enough power for bugs to activate it though the bugs a big… such as ticks, horse files, bot fies and small enough for No-See'Ums Gnate and fruit flies. I see to put a small fan in place so once the bug wnters it will be directed forcing the size of the insect toward th area built to zap that insect's size.
WD-40 and a lighter will ALWAYS work. And no electronics. Lol. Works on spiders as well
Im not evil….BUUUUTTTTTTT , lets be honest….how many people wanted Clive to be Zapped!!!
That PNP transistor is actually held off until the led circuit voltage increases which also means the led boost converter is loaded by the transistor base as well.
The circuit looks fairly straight forward. When the LED is off, the PNP transistor is an open circuit because the base and emitter are at the same voltage, and does not load the battery. When the LED is on. The collector will be around 2.2 volts which shifts the bias on the oscillator transistor enough to unblock the base and allows it to respond to the feedback and oscillate.
The common terminal of the voltage multiplier should be the anode of the left most diode. The 470n capacitor should probably be between that anode and the cathode of the right most diode. What is neat about the Cockroft-Walton multiplier is the individual capacitors and diodes can have fairly low breakdown voltages, much less than the output voltage. Using the diode as a safety discharge is weird, a 10K resistor would be fine, maybe a chip diode is cheaper than a resistor.
I have the same cheap meter minus the blue bumper. It is actually a pretty good meter considering it cost $4 US. The DC accuracy is quite good, but the AC sensitivity isn’t too exciting. The DC input resistance is 1 Meg and the AC input resistance is 707K (guess why that is…). Yes, the low range current input is fused. The 10 amp input is not fused. I bought a whole box of these meters so students could measure TTL and CMOS switching threshold and current draw simultaneously in a digital fundamentals course I teach. Yeah, it is a low tech approach, but it seems to really help students get the point.
When we were kids we use to test 9volt batteries with are tongues. Mike west Nephew borrowed phone
A bjt is cheaper than a diode. That's the oldest engineering trick in the book. Also, a nand is cheaper than an inverter. 😉
"I think we should take it apart"
The dreaded words my folks hated when I was knee high to a grasshopper, as I took Everything apart to see what made it "Tick"
And "Dreaded" due to the fact that not everything went back into a functional product when I was done 🤣
The people who disliked this video enjoy bug bites.
I've have seen versions of these Solar Zappers in swimming pools to kill bugs
Huh… Well, I think using a single pole double throw switch to discharge the output capacitor when switched off is quite clever. But yeah, I also can't think of any good reason why they would use a diode instead of a resistor. The way you drew the diode in the schematic though, the capacitor would drain through the diode in reverse direction. Maybe they use the diode to discharge the capacitor quickly at first and then slow down as the voltage decreases? Not that that would have any reasonable advantage though. No idea, strange…