Archive for August 30, 2011

Rigol DP1116A and DP1308A Programmable Power Supply Review

Rigol Power Supplies

 

In this episode Shahriar reviews the brand new Rigol DP1116A and DP1308A programmable power supplies. Furthermore, the power supply features are compared against an Agilent dual output power supply.

“DP1308A & DP1116A are high-performance programmable linear DC power supply. They have excellent features including timed outputs and tracking capabilities; extremely clean  ripple and noise, comprehensive over-voltage, over current, over-temperature protection, a large and clear user interface, super performance specifications,and  multiple standard interfaces. The DP1308A & DP1116A meet the requirements of various forms desktop and integrated system testing. DP1308A & DP1116A are widely used in research and development, education, industrial control, mobile communication, and product testing, etc.”

The MSRP for both products is $849. Rigol offers a 30 day no-questions-asked return policy and a 3 year warranty. They also provide an excellent local technical support out of tropical Cleveland, Ohio.

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Op-Amps, PWM and Ignition Coils Tutorial

Op-Amp

 

In this episode Shahriar discusses methods for generating a pulse-width-modulated (PWM) signal entirely in the analog domain by employing operational-amplifiers (Op-Amps). A total of four op-amps from a single power supply are used in unity-gain negative feedback, astable positive feedback, integrator and open-loop comparator configurations. The theory of operation as well as measurement are also presented. This episode also includes a quiz. Please post your answers in the comment section.

As a final experiment, an ignition coil is used to generate in excess of 20k volts! The combination of the PWM circuit and the ignition coil provides a stand-alone fully analog high voltage power supply.

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Frequency Generation: Crystals and Ring Oscillators

Crystal

 

In this episode Shahriar takes a look at the challenges associated with signal generation for the purposes of timekeeping. More specifically he digs deep into the workings of crystal oscillators and even takes apart some vintage crystals to reveal whats inside! He also shows how this type of circuits can be characterized and compares the performance of a crystal oscillator with that of a ring oscillator under temperature and power supply variations.

 

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