Archive for the ‘Power Supplies’ Category:

2021-05-11 Power Supply Protection Diodes

First off, *all* power supplies should have what this one has. A high current diode across the output jacks, cathode or banded end to positive. This is to protect the output from reverse voltage. A high current diode across the 2N3055 pass transistor, cathode or banded end towards the collector. This protects the transistor from

(Read More…)

2020-09-05 Capacitive Dropper Failures In 240 VAC countries

From a comment I left in Big Clive’s youtube video In the past I’ve seen Clive having to replace “used up” capacitors in the ‘capacitive dropper’ circuits of low cost line operated devices. The problem seems to be common in other countries but here in the US I haven’t seen any problems with the

(Read More…)

2020-09-03 Distributed Generation And Islanding

There is a lot of concern for safety when DGs (distributed generators) are connected to the power grid. The grid operators must ensure that none of the DGs feed back into the grid when the grid generator is not operating. They go through several scenarios in this article. From what I see the DG

(Read More…)

Tags: , , ,

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

(Read More…)

2017-09-23 Cellphone Charger Secret Circuit

Posted to FB Arduino group Sep 23 Mbihi Oliver Four hours is twice as long as 2 hours with the correct charger.  Here is a secret many don’t know:  Smartphones don’t necessarily charge at maximum, especially if they’re charged by a charger not made for their phone. Smartphones often have a sensing circuit that checks

(Read More…)

2017-06-15 Capacitor Leakage Tester Ideas

I was asking about very old capacitors and their shelf life on FB vintage test equipment group.  The guys tell how good the old capacitor testers are because they have the “magic eye” to check for leakage. I was thinking that it would be easy to test any capacitor for leakage.  All that’s needed is

(Read More…)

2017-06-01 How To Disable 5V Regulator?

I’ve been getting PC boards that have all the chips operating at 5 volts, but the input voltage has to be between 7 and 12 volts.  The board has a 5 volt regulator on the board, and often it is a surface mount chip.  But I have dozens of 5 VDC, 1/2 amp AC adapters,

(Read More…)

2017-05-04 Interrupting The Supply V to the Oscillator

I was working on the 27 MHz oscillator for testing the regens, and I thought it would be a good idea to turn the carrier off for a small fraction of a second every 1 or so seconds.  So I built a two transistor flasher with a third transistor to invert the pulses.  Instead of

(Read More…)

© RustyBolt.Info/wordpress