#FreePCB via Twitter to 2 random RTs

BP

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

from Dangerous Prototypes http://bit.ly/2x212mg

Fuzz Factory replica

IMG_4021

Adam Zeloof made his own guitar pedal based on the Zvex Fuzz Factory:

The Z.VEX Fuzz Factory is an amazing little fuzz pedal designed by musical and electrical wizard Zachary Vex. I was introduced to it through Matt Bellamy‘s unique guitar style, and fell in love with its out-of-this-world sound. While I was tempted to buy a Z.VEX original for their beautiful hand-painted cases, I decided to save a few bucks and make my own.

See the full post on his blog.

from Dangerous Prototypes http://bit.ly/2xbjdpH

App note: Gate-source voltage behaviour in a bridge configuration

an_rohm_sic-mosfet_gate-source_voltage_an-e

App note from ROHM semiconductor on MOSFETS and IGBTs. Link here (PDF)

Power switching devices such as MOSFETs and IGBTs are used for various kinds of power supply applications, power supply line switching components, and other power applications. In addition, the circuit topologies used are diverse, parallel and series connections are widely used, not to mention single device use. Especially in bridge circuit configuration, in which the devices are connected in series, it is common to turn on and turn off each device alternately. Due to the current flowing and the voltage change in each device, the devices greatly affect one another. In this application note, we focus on Gate-Source voltage in MOSFET bridge configuration based on one of the simplest power circuits, a synchronous rectification boost converter to understand the switching operation in detail.

from Dangerous Prototypes http://bit.ly/2XWQO2o

App note: Board level application notes for DFN and QFN packages

an_on_AND8211-D

Board mounting an DFN/QFN (Dual/Quad Flat-Pack No lead) application note from ON Semiconductor. Link here (PDF)

The DFN/QFN platform offers a versatility which allows either a single or multiple semiconductor devices to be connected together within a leadless package. These guidelines include printed circuit board mounting pads, solder mask and stencil pattern and assembly process parameters.

from Dangerous Prototypes http://bit.ly/2XQcmgX

Simple digital clock with PIC16F628A and DS1307 and 7-segment LED display

DigiClock1

A simple digital clock with PIC16F628A + DS1307:

In this new project I am again using PIC16F628A microcontroller. The goal is simple digital clock with 7-segment LED display and the clock will have no additional functionality – no alarm, no seconds digits, no date. The latter can be added in the software though. For the RTC chip I chose DS1307. For the LED display I used Kingbright CC56-21SRWA.

More details on DIYfan blog.

Check out the video after the break.

from Dangerous Prototypes http://bit.ly/2WHmxTw

Phase-locked inverter

circuit1

Here’s a great write-up on building a phase-locked inverter from mitxela.com:

 The input is at 50Hz and the output is at 60Hz. So for every 5 input cycles, we want to generate 6 output cycles. We will be synthesizing a sine wave in software, and there’s no reason not to go with a conventional lookup table of 256 bytes. The PWM will be averaged out by the coils in the motor. It may even be possible to drive it with a square wave, but there is a self-starting mechanism I don’t want to interfere with. A synchronous single-phase motor normally will spin in either direction, and if you want it to spin only one way (as is the case with a clock) extra components are needed. It could be a mechanical pawl that stops it starting in the wrong direction, but the rotor spins very freely in either direction when the clock is powered off. More likely, there is a capacitor and/or additional coils which provide the shove in the right direction.

Project info at mitxela.com.

from Dangerous Prototypes http://bit.ly/2IawxAJ

#FreePCB via Twitter to 2 random RTs

BP

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

from Dangerous Prototypes http://bit.ly/2WDs02t

PortL2 – Portable electric vehicle charger

portl2_before_installation_elr

Here’s a project log covering the build of a portable level 2 electric vehicle charger by Andrew Rossignol:

This is a battery-powered EV charger that allows destination charging where L2 charging is not ordinarily available. This can be used as a range extender for electric vehicles with smaller batteries. This system has a ~7kWh battery which should charge my Cadillac ELR to more than 60%. This has been a fun project with plenty of lessons learned.

More info at The Resistor Network.

Check out the video after the break.

from Dangerous Prototypes http://bit.ly/2F3DG3U

App note: Why honest weigh scales are application specific

App note from Maxim Integrated discussing strain gauge and accompanying circuit are used in today’s weight measurement applications. Link here (PDF)

Current laws and regulations require honesty, tolerance, and accuracy in weigh scales. The most commonly used weight-measurement element is the strain gauge. This application note explains how strain gauges are useful in multiple applications that must measure stress and pressure and their effects. The electronics of honest weigh scales are varied, and can provide the resolution and accuracy that each application demands.

from Dangerous Prototypes http://bit.ly/2MAyNW9