Product Overview
Siemens B30C600-B Selenium Bridge Rectifier, 30V AC In and 600mA Out, Unused German Old Stock
Condition
One unit, unused new old stock, and the owner rules the condition excellent: no visible damage, corrosion, or anomalies. Evaluation was visual only. Function testing was not performed and no documentation is included, so treat the photos as the spec for this piece. The marked face carries the Siemens logo and the word SIEMENS, the line B 30 C 600-b, a second line reading F 1107, and Made in Germany, with the terminal functions printed beside the lugs in the same black ink: two tilde marks for the AC input, a plus and a minus for the DC output. The bright metal cover shows fine scratch lines on both faces, and the opposite face is blank with no markings visible in these photos. A reddish-brown layer shows along the exposed edges of the plate stack, and all four flat terminals look straight and unbent with no solder visible on them.
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Product Overview
A Siemens full-wave selenium bridge rectifier rated 30V AC in and 600mA DC out, built as a metal-clad flat pack with four flat blade terminals, two leaving each end of the stack. The printed marking reads B 30 C 600-b, spaced and with a lowercase suffix letter, and it is the same part number written B30C600-B in catalogs. The German designation reads straight off the face: B for the bridge, 30 for the AC input in volts, C for a capacitive load, 600 for the DC output in milliamps. Terminal polarity is printed on the cover in black ink, two tildes for the AC side and a plus and a minus for the DC side, so the part tells you how it wires in without a datasheet at your elbow. A second line reads F 1107; we treat that as a factory marking and do not confirm what it encodes, and it is not a catalog or order number. Against the millimeter ruler in the photos the metal-clad body measures approximately 45 mm by 35 mm, with the terminals bringing the overall span to roughly 68 mm, and a round opening sits at each end of the cover. Selenium rather than silicon is the whole point of the part: it is what a tube-era low-voltage supply was designed around, and its higher forward drop is a characteristic of the chemistry, not a fault in this piece.
Key Features
- Full-wave bridge rectifier built on selenium, not silicon
- Maximum AC input: 30V
- Maximum DC output current: 600mA (0.6A)
- Four flat blade terminals, marked +, -, ~ and ~ on the body
- Metal-clad flat-pack body, approximately 45 mm by 35 mm against the ruler, roughly 68 mm overall across the terminals
- Marked SIEMENS with the company logo, B 30 C 600-b, F 1107, Made in Germany
- A round opening at each end of the metal cover
- Forward voltage drop and output under load: not confirmed - verify against the datasheet before use
Applications
- A restorer rebuilding a tube-era German radio or amplifier supply that was designed around a 30V selenium bridge and wanting the original chemistry back in the chassis
- A collector keeping a chassis period correct on the underside as well as the top, rather than hiding a modern silicon bridge behind the same four terminals
- A bench tech feeding a low-voltage DC rail in vintage test equipment that used a selenium bridge of this rating
- A builder measuring selenium against silicon forward drop on the bench before deciding how to rectify a restoration
Frequently Asked Questions
Can I drop a modern silicon bridge in instead?
Not as a straight swap. Selenium has a noticeably higher forward voltage drop than silicon, so a silicon bridge in the same spot raises the DC output voltage and can stress whatever sits downstream. The usual remedy is a series dropping resistor sized against your measured load. Restorers who want the original voltage behavior and the original look go the other direction and hunt for a selenium unit like this one.
What is the forward voltage drop, and what will it actually deliver?
Not confirmed. Forward drop in a selenium stack varies with the individual unit and its history, and this one has not been powered here. Verify against the datasheet before use, and measure the output under your actual load before you commit a restoration to it.
Is there a safety issue with selenium rectifiers?
Selenium is worth respecting. A selenium rectifier that fails or is run past its ratings can release acrid fumes with a distinct sulfur odor, which is a known characteristic of the chemistry rather than a defect in this piece. Bring it up gently, keep it inside the marked 30V AC and 600mA limits, give it air, and do not walk away from its first run.
It is unused stock but sold untested. What am I taking on?
Exactly what the photos show, and nothing hiding behind them. This one was inspected by eye and never powered, so the electrical unknown is yours: a selenium stack that has waited decades can read leaky or high in drop even when the cover looks perfect, and nothing but energizing it will settle that. What we can hand you is the visible evidence, so the markings, the four terminals, the plate stack edges and both faces of the cover are photographed against a ruler instead of summarized in a sentence. Shipping is a flat $8, free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
Before silicon took the job, a stack of selenium plates in a metal jacket is how a power supply made its DC. If your restoration wants the original chemistry instead of a silicon bridge with a dropping resistor bolted alongside, this one is unused and waiting for the assignment.
