Current Mirror Segments – Part 1

A current mirror is a circuit segment that functions to produce a copy of the current flowing into or out of an input terminal by replicating the current in an output terminal. In the analog […]

Automotive SSR Module v1

After getting a few vintage automotive solid state relays (SSRs) from a flea market thru a friend abroad, I decided to make a low-cost automotive solid state relay myself. So, this post covers the design […]

Automatic USB Mains Switch (v1)

Recently I wanted to build a USB controlled power strip that powers some peripherals as soon as my computer starts up. Luckily, I managed to find a commercial USB-Power On switch in my attic (see […]

Handy Test Light (v1)

Get ready to make a high-resistance continuity tester pen that runs on a pair of common 1.5V AA batteries. This design is based on an idea from a Chinese website but with a few modifications. […]

CD4541 Programmable Timer IC Cheat Sheet

Today we are going to inspect the CD4541B CMOS programmable timer IC. The CD4541B programmable timer chip has a 16-stage binary counter, an integrated oscillator for use with an external capacitor and two resistors, output […]

Doorbell Sensor IoT Module (v1)

In this post, I will attempt to share the design idea of a doorbell sensor that can be build using just a handful of inexpensive and easily available electronics components. When cleverly integrated into your […]

4V SLA Battery Charger

Pretty little 4V Sealed Lead Acid (SLA) or Sealed Maintenance Free (SMF) batteries are widely used in portable electronic gadgets such as mosquito bats, kitchen scales, healthcare instruments, etc. The most common 4V SLA rechargeable […]