Low-Cost Voltage, Current and Resistance Reference

 

 

This tiny module uses a 3V lithium coin cell, a voltage reference i.c., a precision resistor and little else! It provides a :

• Reference voltage of 12.5V ±1mV (±0.04%).
• Resistance of 1k ±1Ω (±0.1%)
• Current of 2.5mA ±3.5µA (± 0.14%)

It can be used for checking or calibrating multimeters or anywhere that an accurate and stable voltage is required. It’s low power design has an auto-off function, power LED and its battery is good for over ten years with intermittent use.

 

Surface mount design needs good soldering skills

 

Special feature: checking and calibrating multimeters

 

Multimeters tend to drift off calibration quite markedly as the years pass by. So how old is your multimeter and has it ever been checked? This special feature explains how to use our Low-Cost Voltage, Current and Resistance Reference project to bring your multimeter back up to scratch.

 

USB Power Monitor

This LCD module measures current, voltage and power of a USB port, by connecting in between the USB port and the connected USB load. The auto-ranging design measures from a few microamps up to over an amp, and displays power from milliwatts to watts.

 

Includes display flip mode, mode memory and digital calibration. PIC 18F45K80 based, requires source code (hex file) available free from our Library as usual.

 

Surface mount design needs good soldering skills

 

Driveway Monitor – Part 2

Last month we introduced our new Driveway Monitor and described how it worked. In Part 2 this month, construction, testing and installation are described. Various options are also outlined, so you can build it to operate just the way you want, and the solar charger aspect is explained as well.

 

Teach-In 2016 Part 7: Arduino Nano

If you’d like to get up to speed with Arduinos then our latest Teach-In series is just for you. In Part 7 this month, the Arduino Nano (picture, right) is explored. This diminutive device offers a highly cost-effective alternative to the Uno (picture, left) that’s compact enough to tuck away into the smallest of spaces. This month’s Arduino Workshop suggests a passive infra-red (PIR) motion sensor, and Coding Quickstart looks at tone generation.  An Arduino Nano-based PIR motion alarm is described as our Get Real project.

 

PIC n' MIX

 

PIC and the PICkit 3: A beginner’s guide (Part 3)

In Parts 1 and 2 in previous months the basic concepts of PIC circuit development were covered, from MCUs and MPUs, to programmers, compilers and IDEs. Part 3 continues with an exploration of Microchip’s MPLAB X IDE. It's an excellent introduction to using PIC microcontrollers with today’s modern tools, not to be missed!

 

Net Work 20^th Anniversary

Celebrating 20 years of writing our Net Work – the Internet column, Alan Winstanley recounts the history of the Internet, how it all started and how EPE embraced the web twenty years ago. First in a two-part special article.

 

^ Brother EP-44 Mobile Email solution, 1986

 

Cold War Computing/ SAGE USAF Video

SAGE Youtube Video (correct URL)

 

^ A SAGE (Semi-Automatic Ground Environment) operator checks a scope reading with a light-gun. Still from the USAF movie

 

A PDF of the author's original 1996 article (The 'Net - What's in it for you?' , from which Net Work was originally created, is downloadable from EPEMag.Net

 

Also in this month's issue:

 

• Techno Talk – radio ‘astrology’ is not nonsense!
• Interface – Capacitance Meter Mk 2
• Circuit Surgery – the mechanics of using ammeters and voltmeters
• Audio Out – super simple retro amp-speaker combo (Part 2)
• Max’s Cool Beans – diorama effects controlled by an Arduino

 

Next month

Compact, hybrid switched mode 100W Bench Supply (Part 1); Speedo Corrector; LED Party Strobe; Teach- In 2016 (Part 8) - infra red controllers using Arduino

 

EPE is packed with practical electronics projects and theory for the hobbyist. You can order a printed copy of EPE for delivery to your door (worldwide), or try the PDF Version (needs Adobe Reader for Windows), or the Pocketmags for your mobile device. Subscribe now!

 

 

 

Source code file 0816.zip

 

Download Help

 

Can't find what you're looking for? Our Library Help Page offers extensive information and help with downloading files.

 

The August 2006 issue had plans for a Loudspeaker Level Meter, an Adjustable DC-DC Voltage Converter for cars, a telephone dialer for burglar alarms and a variable high intensity LED torch.

 

PCB artwork

 

As from July 2013 issue PCB artwork is available free to subscribers only.

 

Non-subscribers may purchase artwork files for a nominal sum. Please contact our Orders Dept for information or to place an order.

 

EPE Printed Circuit Boards

 

We can supply ready-made printed circuit boards (8-digit order codes) to the original design specification via mail order or from our Online Shop.