The previous article about a nearly ideal LDO regulator gained quite some interest amongst readers. Meanwhile I managed to build two "barrel" multi-purpose power supplies based on this LDO circuit.
Casing was always the biggest doubt in my DIY projects. Here I resorted to nice and cheap stainless-steel cans from Ikea with covers cut from a 6mm thick MDF. Perfect solution... to be stuck behind the desk.
| 120W barrel power supply |
LDO = low dropout
Ideal Low Dropout Linear Voltage Regulator  |
Such a popular three-pin voltage regulator as LM317 () is specified to work at minimum 3 Volts across the chip. This humble parameter is not even stated directly in the datasheet: I found it only Continue reading
Trivial topic indeed: why one would ever need to protect a circuit from a rolled-over power supply? There are countless potentials for mistakes that can result in an electronic developer pulling out his hairs and staring at his design worth of many hours or days of work - the one that he bricked just a moment ago.
Many of articles on this site might look trivial. So they are. But this is the result of my personal experience: I got tired catching myself re-inventing the wheel again and again. Thus I decided to post whatever proved to be useful for me at least once, in the hope that it might save some time to myself and others in the future.The industry makes it all for you. One can purchase a Solid State Relay (SSR) that would fulfill virtually any imaginable requirements. The only question is money: a decent device capable of handling mains power load of few hundred Watts would cost as from $10 and up. While if we lower the bar and look for an SSR capable of switching say 100mA - it would be possible to get one for less than a dollar.Here is a very simplistic (and relatively inexpensive) SSR implementation that is capable of managing heavy loads. It uses a as the main power switch and a "telephony" SSR controlling it. Continue reading
For this article let's accept an axiom that warming up heaters well before raising B+ is a must for any good behaving thermionic valves based equipment.
LM317 appears to be the most appreciated CCS building block amongst solder-slingers
(term (c) John Broskie).
Personally I never felt relaxed having such a complex OpAmp-based circuit in the audio-signal path. Nevertheless many routinely utilize this type of CCS in audio, including "pure" tube designs.
Recently I was playing happily around cascoding JFETs and MOSFETs for the CCS in my own design. Continue reading
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