6th August 2008

Loudspeaker Fuse Placement for Audio Amplifier to Preserve A Good Bass Response

Hardware

To protect the loud speaker from destructive signal, the most simple way is by placing a fast blown fuse between speaker and the amplifier output. This common solution is depicted in the figure 1 (a).

Figure 1. Fuse Placement to Preserve Good Bass Response
The fuse in the circuit has a significant resistance to generate heat, because [...]

5th August 2008

Anti Burglar Alarm, A Half Lie is Much More Dangerous Than 100% Lie

Hardware

The idea that a half lie is much more dangerous than 100% lie is implemented in this design. Rather than showing off that our car is 100% protected by a sophisticated alarm and protection system, this anti burglar protection circuit prefer to lie that the car is not protected by any electronic alarm or any [...]

10th July 2008

Current Limiting Circuit

Hardware

Introduction
Current limiting circuit often misinterpreted with current/circuit breaker. Unlike a fuse that break a circuit connection, a current limiter only limit the current at a predetermined level. Current limiting circuit can be as simple as a single resistor, but here I present an active current limiting circuit. With a resistor (a passive current limiter) [...]

24th June 2008

AC Line Powered Pilot Light Circuit Schematic

Hardware

The Circuit Schematic

On circuit analyzed today, we will analyze AC Line Powered Pilot Light circuit designed by David Johnson. Using the circuit, you don’t need a transformer to power a standard LED. As always, David Johnson makes his design simple and smart, but he doesn’t talk much about his design. Let’s discuss his design, the [...]

13th June 2008

Using Noise Addition To Improve Measurement Precision

Hardware

What do you think when you read the title of this post? Normally, in any measurement, noise addition to the signal acquired from a measuring transducer is the source of imprecision, then how can I say that we can also use a noise to improve the measurement precision? Yes, we can ad a noise to [...]

13th June 2008

Generating Triangle Wave Using Two Square Wave Oscillator

Hardware

Triangle wave oscillator normally designed with a constant current source/sink to charge and discharge a capacitor. Reading an article on how to get 10 bit reading precision on 8 bit ADC on electronic design magazine today, I got something interesting on how to build a triangle wave oscillator: using two XOR-ed square wave oscillator. The [...]

6th June 2008

Condenser Microphone

Hardware

Condenser microphone is a sound pick-up transducer. The mechanism is based on the characteristic of a capacitor. A capacitor is constructed by two conductor plates separated by a dielectric material (isolator). Air is a common dielectric used in condenser microphone. One plate will be stationary and the other plate will be vibrated by the [...]

6th June 2008

Introduction

Hardware, Software

Vidisonic is my space to share my experience in designing hardware and software solutions. Choosing to work as a hardware and software designer freelancer since 2003 is a hard decision, but I enjoy taking the risk and the benefit. I’ve been learning a lot about building and designing of electronic circuits since 1992, when I [...]