Archive for July, 2018:

2018-07-30 How Are LED Lights Made Dimmable?

From FB comment to Bill Sherman’s candelabra lamps. Bill Sherman Sometimes I wonder what is meant by dimmable. If a LED light uses hundreds of microfarads for the DC filter capacitor, then when the light is dimmed, the long time constant causes it to flash on and off when it is dimmed. So if the

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2018-08-29 High Temperature And Nylon Screws

From FB group Hobby Electronics, 2018-09-01 I faced this dilemma before. I’ve repaired power supplies where the transistor failed because it was not held tightly to the heat sink because of a nylon screw that got hot. I used a steel screw and a fiber washer, and heat shrink tubing over the threads to insulate.

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2018-07-28 New?? Cisco Phone Set

From FB group Bell Telephone… Steve Hart I used to do a shenanigan when we had a Cisco IP phone die. If the ‘factory reset’ didn’t cure the problem, with the help of the ladies, I would give a ‘new’ phone to the client. I would make sure the phone, especially the handset, was cleaned

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2018-07-27 Alan Walker – Faded 1.8 Billion YouTube Views

I’ve watched a lot of YouTube videos totally unrelated to music, and I hear the instrumental version of this over and over, but until now I was never able to find out about it. I had the earworm, I just recorded it and played it while on the road. I found out that since he

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2018-07-26 Transistors, ECG, Motorola HEP Line, etc.

From FB group Building Transistor Radios Wayne Leake Yeah, the 2N3904 is E B C, THE ‘945 is E C B. Watch out the leads don’t touch and short. 😝 I have the Moto HEP catalogs, if you need to find out what it’s equivalent to. When National Semiconductor came out with their catalogs they

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2018-07-25 How Stable Are Regen Reflex Radios?

From the FB group Building Transistor Radios Regenerative / reflex designs are not as stable as superheterodyne radios. One problem is the design depends on factors that are not predictable such as gain and feedback, which are not linear. The regenerative reflex depends on the circuit being on the verge of oscillation, which is not

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2018-07-24 “Boy’s Radio” Reflex Schematic

From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is

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2018-07-24 “Boy’s Radio” Reflex Schematic

From FB group Building Transistor Radios Willie Barnett I see from the schematic that this is a reflex regen. They did something else that is very seldom seen, the volume control acts not as a normal variable voltage divider, but instead as a variable shunt load across the secondary of the driver transformer. This is

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2018-07-22 Newspaper Delivery

From FB group 50s-60s Compton John MacBride Yeah, people don’t realize that the newspapers worked 24 hours, and all the delivery took place at night and early morning. There were neighbors a few houses down that never seemed to have jobs, I think their last name was Humberger. I found out that the L.B. Press

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2018-07-20 My Digital Dice Were Loaded!

From FB group Building Transistor Radios, Jul 27 Rolando Fernández I bought a kit for a digital die (one die of a pair of dice). I assembled it and then I rolled the die many times and wrote down the values to see if it was random. I was shocked! It was loaded! It was

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