Tag Archives: Review

Teardown, experiments and calibration of an Ist-Rees laser spectrum analyzer

via Dangerous Prototypes


Ist-Rees laser spectrum analyzer teardown from The Signal Path:

In this short episode Shahriar takes a close look at an Ist-Rees laser spectrum analyzer. This simple instrument is based on a continuously rotating diffraction mirror to detect various wavelengths. A trigger signal is used to denote the beginning of the scan and the front-panel display shows the current selected wavelength. By aligning the output signal with the trigger signal the wavelength of the input light can be measured.
After the unit teardown, the instrument is used to measure the wavelength of a semiconductor 1310nm laser. The unit is calibrated using this source and is then used to measure the infrared leakage wavelength from a green laser pointer.

Check out the video after the break.

Tear down of a super capacitor

via Dangerous Prototypes

A teardown video of a 1 Farad super capacitor from Electronupdate:

In a recent video on the tear down of an electrolytic cap a viewer was wondering what a super capacitor looks like.
They have much more capacitance: 10,000 time more on average for the same volume.
Surely this means the physical construction must be amazing! Interestingly enough, the construction is almost identical.. the secret is in the dielectric.

More details at Electronupdate blog.

Curtis 1231C-8601 500A PWM DC motor controller teardown

via Dangerous Prototypes


Jay did a teardown of a Curtis 1231C-8601 500A PWM DC motor controller:

The Curtis 1231c-8601 power board is relatively simple. It uses 18 MOSFETS in parallel to switch current from the motor- terminal back to the battery- terminal (the motor+ lead is already connected to battery+). The MOSFETs it uses are IXYS IXTH50N20 SP9536 chips. The center lead is bent up over the chip and soldered to a ring terminal, such that the screw that attaches the chip to the heat sink also electrically connects that pin to the heat sink.  Most chips that attach to a heatsink have a metal back, but the IXTH50N20’s used here do not, so it appears that they had to take extra assembly steps to electrically couple it to the heatsink.

More details at Jay’s blog.

Solar battery charge controller teardown

via Dangerous Prototypes

A teardown video of a solar battery charge controller from Electronupdate:

A solar battery charger: one side goes to a Solar Panel, the other to a lead-acid battery. A charge controller allows the battery to be safely charged.
Snagged off of Amazon. Seemed really cheap at $17.36.
A look at the assembly quality tells me why. Bad soldering, mechanical errors, wrong wire sizes….
What is baffling, however, is that many of these workmanship issues (beyond the missing “fuse”) are just due to lack of attention… i.e. it would cost no more to do it right.

More info at Electronupdate blog.

Teardown of a Vivitar Rapid battery charger

via Dangerous Prototypes


Kerry Wong did a teardown of a Vivitar rapid battery charger for the NP-FW50 lithium-ion battery pack used in Sony A6000 digital camera:

The circuit board itself though looks surprisingly clean and well designed. It does not use any dedicated lithium ion battery charging ICs however. Rather a MC34063A buck/boost DC-DC converter chip is used to provide the current limited 8.4V constant voltage. This arrangement is less ideal then the typical lithium ion battery charging technique. Typically, the charging current is held constant until the voltage reaches a certain threshold and then the charger switches to constant voltage mode. Once the charging current drops under a predetermined threshold the charging is done. The charging current under constant voltage charging however, monotonically decreases from the get go so it usually takes much longer to obtain a full charge. But the good news here is that overcharging is unlikely as the charging voltage is fixed to the correct battery terminal voltage.

More details at Kerry Wong’s blog.

Check out the video after the break.