This may be helpful when choosing the amount of capacitance for a certain unregulated AC power supply – the kind that uses an old fashioned transformer. It calculates one variable given the others. https://www.chipbuilder.com/full-wave-power-supply-ripple-calculator.html
2020-09-05 Capacitive Dropper Failures In 240 VAC countries
From a comment I left in Big Clive’s youtube video https://youtu.be/jgaCYRc1-og 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…)
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…)
2017-05-21 22-120 Power Schematic Errors
Posted to FB group 2017 June 8, then a copy here. I found this Radio Shack power supply on Bama.edebris.com. Looks like someone drew it up. I found a few boo-boos, one being the LED having a 100k current limiting resistor. It’s not going to be bright. I wonder if BK1 thermal breaker is capable
(Read More…)
2016-10-04 Joule Thief Powers Field Strength Meter
There are many circuits that are used infrequently that are powered by the usual 9 volt battery. One of these happens to be a field strength meter (FSM), which is used for detecting the power output of a transmitter such as the one a radio amateur uses. Some FSMs are very simple and use no
(Read More…)