Power Management, Chapter 8: Power Management ICs | Circuit Breaker Parts

These ratings on the data tag tell us exactly what minimum ampacity the circuit must be capable of carrying as well as the maximum size the circuit breaker or fuse may be able to protect the circuit against in an overcurrent condition.

No, he is using a MC3041 to drive a BT137 which can handle 8 amps continuously (if properly heatsinked).

And it’s is a bad advice from ESD protection standpoint as well because nothing else, like your table where the new components are laying on, isn’t grounded so you’ve just created a potential well.

The basic concept of your point is looney. Voltage doesn’t cause heat, The only thing heat dependent for a given installation is the current – of which 120 volt charging is usually less than 240.

• Circuit conditions such as the peak voltage and current during the surge event • The MOV continuous operating voltage (should be at 20% above maximum system voltage under normal conditions) • The number of surges the MOV must survive • Acceptable let-through voltage for the protected circuit • Any safety standards with which the circuit must comply

One of the best demonstrations I’ve ever seen, was at the Dayton hamvention. DP&L (Dayton Power & Light) set up several short poles with standard 7200 to 220 center tap transformers. By back feeding the secondaries with 220 from the breaker box, they could energize the 7200 lines and began demonstration what happens when you encounter these wires with numerous items. Antenna masts, kite strings, and even a hot dog were used to show the immense power available, and the audience was always suitably impressed.

Electricity is complicated and dangerous. If you don’t know what you’re doing, you could start a fire or get electrocuted—sometimes fatally. Pretty much anything beyond plugging something into the wall should be left to a professional. The cost of my visit is nothing compared to the price of your safety. Here are 12 more home improvement projects you should never DIY.

Neutral is connected to Earth Ground at your electrical panel. Circuit breakers interrupt the LINE only so I’m not sure what you mean by soil resistivity and current flowing in earth ground. 500 micro amps flowing or rather, leaking through Earth ground is usually all that’s allowed by UL in cord-connected products.

As someone who started playing with electronics in the days of B+ in the 350VDC range with double that across the main xformer’s secondary, I was utterly appalled at the idea of tying myself to a hard ground when working with some of the newer (for the time) solid-state stuff that was coming out. We had a respect for high voltage then that is often missing these days, this article is an excellent reminder that this is still needed.

Step 1:  To find the voltage rating of the MOV, allow for 20% headroom to account for voltage swell and power-supply tolerances: 24 V dc × 1.2 = 28.8 V dc. Given that no varistors have a voltage rating of exactly 28.8 V, check the datasheets for specifications for 31-V dc MOVs.

24v 12a is not that much more at 288watts. I’m sure I’m missing something to do with electromagnetism which makes the secondary unnatractive?

The first was working with a bench buddy on a military SSB Shortwave amp. My bench buddy assured me he had powered the system down and unplugged everything necessary, and I trusted him. I reached in with a pair of needle nose pliers to remove the plate voltage supply on the amp tube, and got hit by 26kv DC. Shouted and was teleported backwards about 3 feet, but no damage done (except a small melted bit on the end of the pliers).