Everything for Electronics

Unanswered Questions

Wireless Water Level Monitor/Indicator September 2012

I'm looking for a schematic solution to wirelessly indicate the water level of a distant water tank more than 100 m away.

via email

Fiber Optic Fusion Splicer July 2012

I am looking for some technical information for repairing various fusion splicers on the market such as Fitel, Sumitomo, and Fujikura. Anybody have any information they are willing to share?

Glendale, AZ

Vintage Transformers January 2012

I have some industrial equipment inherited from a deceased customer. Two transformers, vintage WWII, 10 and 5 KVa and one transformer probably, 15 KVa with SCRs but no control board. This equipment was originally intended for wire heat treat service, 28 VAC secondaries. I have had them 20 years or more. I’ve been trying to cook up a stable circuit for firing SCRs for all the transformers. I have worked with such circuits all my professional life but [now 76 yrs] stability is eluding me. Industrial electrical service is always noisy and welding especially so. I know I need zero crossing sync and I need 0.008 sec to zero sec adjustability for the triggers. It must also be jitter free. This is just a hobby because nobody buys antique transformers except for scrap, which might be my best business decision considering the times. I do have the transformers and the SCRs. My heirs can scrap the units out after my reward. I have lots of scrapables to play with and nothing else but time.

Robert Gibson
Aurora, IL

Troubleshooting January 2012

How does one replace a spider IC?

Enugu, Enugu

Self-Powered Current Switch January 2012

I would like to know how to build a self-powered currect switch to monitor a lamp pole light. I need it to output an open or closed contact, so I can sense if there is current or not.

The light pole voltage is 120V at a range of 1A-10A. Anything above 200-500 ma current is on or closed contact. Otherwise, no current, open contact. I need it as small as possible and over-voltage and over-current protected.

Any help out there?

Christopher LeFrois
Lincoln, NE

Power Supply For Fluke 8050A and 8600A January 2012

I have a couple of older Fluke 8050A and 8600A multimeters that were outfitted with battery options. The batteries are long gone and I never really used them anyway. I would like to use them as bench only meters and reconfigure them to a non-battery type supply. Does anyone have an internal power supply plan that I could use in these meters without drilling holes in the cases and cutting up traces on the circuit boards? Something using capacitors, diodes, etc., that would fit into the battery area and plug directly into the battery connections.

David Asselin
Saint-Lambert, Quebec

Audio Electronics February 2012

I want to construct an audio amplifier which will have a USB input for audio songs. Previously, I have constructed many audio systems, but now I want to add USB input where I can get songs just by pluging in a USB stick or memory card.

Sohail Anjum
Islamabad, Pakistan

RF Security Fence February 2012

I have buried two insulated wires about a foot apart and maybe six inches deep around the perimeter of my yard. The idea is for a security fence that will detect people/animals/cars. The theory is one wire transmits the RF signal, while the other is a receiver. Any change in signal (and some PIC processing) will flag an intruder. I can’t get it to work.

Has anyone tried this and/or can offer any advice?

Frederick M. Raposa
Vallejo, CA


I think a buried antenna will not radiate very much.

George Powelson

Wire Termination February 2012

What connectors seem to be the choice of electronics hobbyists when assembling electronics projects on perf board? Also, is there a standard regarding the spacing of the "perfs" on the boards?

Don Henderson
Tewksbury, MA

Sensor Cable March 2012

I'm looking for a cable that sends an input to the PLC when touched. Any suggestions?

Denver, CO

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