Created; < 2011, Changed 21/02/2022, 08/07/2023 


1950's Germanium bipolar junction power transistors alongside modern surface mount, Silicon MOSFET power transistors.

OC28, OC35 (5-8A or 25-35V) and IPT60P028G7 Infineon (600V and 75A). 

Secondary breakdown that occurs in Bipolar-Junction-transistors in OC28 and OC35 can only handle the maximum current when the voltage is less than 5V.   

A MOSFET does not suffer from secondary breakdown and so can handle both maximum current and voltage together very briefly.

The green push-button and the calliper battery tester was part of a children's electrical experimental kit.

The flaw in writing about electronics is that young people learn hands-on mostly.  An adult can help by guiding the young person but even then in small pieces.  The kit had a bulb, bulb-holder, calliper style battery checker with a bulb, bell, buzzer and some wire.


The electronics I discuss is mostly analogue electronics which is a key part of all physical electronics design.

I am an electronics design engineer but what I design or use are electronic.   Engineers interpret wishes into a practical solution and work together with scientists who propose ideal solutions.

Negative resistor;

This is a simple and probably a cheaper solution than using an IC with a similar function, such as resettable fuse.

I have been designing and making things since before I went to school.

British Engineering and the TV science fiction.

In light of surveillance, Windows vulnerabilities versus also ease of use how does Linux do compared to Windows?