Charles, Hoping to add a simple flasher to an ultra simple geiger counter I built. I already hear clicks via a piezo and I just want to add a simple count...
It's hard to light an LED with only 1.5 volts. I came up with an idea that might work (see files/images/ledflash.jpg. Choose an LED that doesn't draw current...
... Why not use a simple transistor switch to connect the LED to the batteries directly when a pulse fires? Maybe a cap to lengthen the LED on time... -Pete...
I was thinking that 1.5 volts isn't enough to light an LED, especially as the battery ages. A 1.5 volt incandescent would be my choice, but I like the way they...
Thanks, Charles. Got both the schematic and your suggestions. As I haven't been on vacation since building the alarm circuit, will have to try this out when...
I just built a small device that uses 6 rechargeable 2500 mAh NiMH AA batteries in series. Is it possible to build an external charger to charge rather than...
A good charger is difficult. I think the preferred method is to charge the batteries pretty quickly, basically at a current that should charge it in an hour or...
This is to flash two 60W (12/13.8 volt) lamps, about 4.4 amp draw, back and forth. The idea is have a switch to turn both lights on steady or flashing back and...
I found Techlib's page on http://www.techlib.com/electronics/flipflopflash.htm I still need help with picking the best version. I want POS switching of the...
By experimental aircraft, I assume you mean human-sized. I would imagine that the lights have to be certified in some way, since they're so crucial. If that's...
That circuit looks fine. I would add some power supply protection for the '555 since they're only rated to 18 volts, maybe just a resistor and zener diode to...
Is that correct that there is no connection to the 555 discharge pin?  It's a long time since I've played with a 555 but I believe grounding the reset pin...
Could you please explain how the high voltage generator for geiger tubes works? I would love to understand the theory behind the top circuit on this page: ...
The transformer is acting like an inductor, but with a step-up of two, and the "kick back" when the current is interrupted produces the high voltage. Take a...
It sounds like there isn't enough filtering on the output of your multiplier/rectifier circuit. Describe that part in more detail. Fast transitioning is what...
Here is the circuit: http://img7.imageshack.us/img7/1134/circuit2t.jpg The square wave is generated by a microcontroller, and when the zener diodes conduct...
I tried it without the diode across the primary, and I'm still getting big voltage spikes. I had originally put the diode there to protect the transistor from...
I think you should take the output off of the cathode of the last diode and not the anode. Is that high voltage spike on the secondary, at the left side of the...
You're right about taking the output off the cathode. Thanks! The high voltage spike is on the secondary on both the left and right sides of the first .01uF....
If the diodes were breaking down, your voltage would be lower. Something still doesn't make sense. The voltage shouldn't be able to spike so high. Check your...
I agree; something doesn't make sense. The regular diodes should break down at 600V, and the zener diodes should break down at 500V, so I wouldn't expect a...
I don't have a clear picture of where you are measuring the voltage. If the diodes are working correctly, the AC voltage should be riding on a higher and...
Sorry it took me so long to post again. I got some diodes that are rated to 1000V, and I still saw spikes above 650V at N$5, N$7, and N$6 on the following...
The components leads have inductance that allows the spikes. You might be able to reduce them by using a ground plane with short leads on the caps. I suspect...
Ah, that make sense. I'm using a breadboard with the full lead length. When I have a board made, I'll try a ground plane, and I'll make the lead lengths much...
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