This interesting laboratory (bench) power supply I use cca since the late 90s. I found that there's no mention on the Internet
about this the type - Power Supply 2 (PS2),
so I decided to document it. It is possible that I could not find anything just because it's rather vague type code is sipmly
impossible to google. Common phrase "Power supply" and the single digit "2" can give anythin in the search engine.
This power supply looks quite modern at the outside. Even the parameters don't lag behind modern bench supplies. It is relatively small and flat,
yet provides the output voltage 0-30V and current 0-3A (total, up to 90VA). The voltage is adjusted using two potentiometers (coarse and fine)
the current limit can also be set linearly from zero. The modern-looking front panel has a "touch" control buttons for standby on and off,
LCD display and another 3 buttons which selects the display data (voltage, current, current limit threshold).
Input power is 220V 50Hz 210VA.
But after removing the cover you can feel the history :). Internal layout and components are typical of socialist Tesla production.
You will find metal transistors and operational amplifiers with metal housing, axial electrolytes and other capacitors, diodes with screw, cup
ferrite cores, conventional auxiliary transformer and many other parts labeled TESLA, which we would expect more in wooden TV
cabinet, than behind this futuristic front panel. The supply is probably made sometime around the time of the Velvet revolution (1989).
Its principle is quite modern. There is half-bridge switching power supply with 2x SU160, reminding one of the AT and ATX,
but assembled from old parts. This switching supply is followed by a linear requlation with KD367. Switching power supply controls its output voltage
so that the linear regulator has a small voltage drop and therefore worked with small losses, no matter what the voltage at the output
terminals is.
Unlike supply with conventional power transformer it is therefore smaller, lighter and more efficient and do not have giant heatsink. Thanks to
linear regulator it is well-filtered and stabilized and the current limiter has very fast response.
