Contents
Vol.35, No.3
March 2022
12 The History of Transistors, Pt1
24
Since their invention nearly 75 years ago, transistors have reshaped the
world. This series of articles will cover the most interesting bits of their
history and describe how manufacturing methods have changed over time.
By Ian Batty
Semiconductors
44 All About Batteries, Part 3
In the final part of our series on batteries, we cover one of the ‘bigger’ uses
of batteries in electric vehicles such as cars, bikes and even aircrafts and
submarines.
By Dr David Maddison
Science
35
79 Advances in Drone Technology
Quad-rotor drones have been extensively tested and used, so what does
the future have in store for VTOL (vertical take-off and landing) drones? We
take a look at how quad-rotor drones and quadplanes could be improved.
By Bob Young
Drones
96 A Gesture Recognition Module
79
The CJMCU-7620 can sense and recognise gestures made with your hands
and can be connected to an Arduino or Micromite. It comes as part of a
module sized just 16 x 20mm for under $20.
By Jim Rowe
Low-cost electronic modules
24 Capacitor Discharge Welder, Pt1
Build your own safe, low-voltage mini spot welder, which runs from a 24V
DC supply. Despite this, it can deliver over 1000A. This CD Welder is perfect
for making your own thermocouples or even battery packs!
By Phil Prosser
Tool project
35 Raspberry Pi Pico BackPack
This BackPack design simplifies interfacing a Raspberry Pi Pico with a 2.8inch or 3.5-inch touchscreen. It also includes some extra capabilities, such
as a real-time clock, infrared receiver and more.
By Tim Blythman
Raspberry Pi Pico project
68 Amplifier Clipping Indicator
It’s good practice to determine whether your amplifier is about to run into
clipping, as it can potentially damage your speakers. This project will show
you even the briefest of clipping events, to help keep your speakers safe.
By John Clarke
Audio project
84 Dual Hybrid Power Supply, Pt2
The final part in this series focuses on assembling and calibrating the
Power Supply. That includes preparing the heatsink and case, mounting all
the modules and wiring them together, including the mains wiring.
By Phil Prosser
Power supply project
Cover Image: A Texas Instruments SN7400 quad NAND gate from 1965 – https://w.wiki/4mri
2
Editorial Viewpoint
4
Mailbag
61
Serviceman’s Log
72
Circuit Notebook
100
106
1. Alternative Arduino Power Supply
2. Illuminated doorbell press switch
3. Reading three digital signals with a
two-channel oscilloscope
Vintage Radio
Phenix Ultradyne L-2 by Dennis Jackson
Online Shop
108
Ask Silicon Chip
111
Market Centre
112
Advertising Index
Dick Smith Competition: winners have
been notified; full details will be in the
April 2022 issue of Silicon Chip.
