2CL2H Power Frequency HV diodes 12KV 200mA 50-60Hz

Product Overview

The 2CL2H is an axial-leaded rectifier built for the DC side of mains-frequency high-voltage supplies. It blocks up to 12 kV in the reverse direction and carries an average forward current of 200 mA, which puts it in the rectifying stage of equipment where the waveform is a rectified sine at 50 or 60 Hz rather than a switching edge.

That line-frequency role shapes the whole part. A power frequency diode is chosen for blocking capability, a stable forward drop and predictable reverse leakage; recovery time is not specified because it is not the limiting parameter in these circuits. Design teams use them in the high-voltage tanks of X-ray and DR generators, dental and panoramic imaging supplies, industrial NDT sets, DC high-voltage testers, electron accelerator supplies and transformer-driven multiplier strings.

Each of these high voltage diodes is a black molded cylinder with silver axial leads. Leads can be formed to a chassis or a board footprint before soldering, the body is small enough to sit inside a compact tank, and because the part is wired rather than surface-mounted, the joints can be inspected and reworked after assembly. A white band at one end marks the cathode.

HVDIODE has been building these parts since 2008, and the 2CL2 series is its power-frequency range, with several voltage classes sharing the same axial construction — where a design needs more blocking headroom than 12 kV, a higher-voltage member of the series is the part to specify. We are high voltage diode manufacturers, and the series, its package drawing and its test data all come from our own plant in Anshan.

Key Features

• Axial leaded connection. Both leads exit the ends of the body, so an axial high voltage diode can be wired point to point, threaded through a PCB or fixed to a chassis before soldering. In oil-filled tanks and potted modules this is often easier than a surface-mount footprint, because the joint stays accessible for inspection and rework.
• High thermal conductivity epoxy molding. The chip is encapsulated in an epoxy compound selected to move heat from the junction to the body surface and out along the leads. In an air-cooled build that molding is the main heat path; in oil it keeps the chip protected while the surrounding medium does the cooling.
• Low internal resistance. Conduction losses stay small at the rated 200 mA, so a power frequency diode runs cooler in continuous DC duty and leaves more of the ambient range in reserve. That matters in supplies that run for hours rather than in short bursts.
• Special passivation glue chip protection. The chip surface carries a passivation layer before encapsulation, which keeps the blocking junction away from moisture and ionic contamination. Reverse leakage stays predictable, which is what high voltage diode manufacturers look for in a measuring or imaging supply.
• Excellent discharge characteristics. Multiplier strings, test sets and capacitor-discharge circuits expose the diode to fast-rising voltage and stored charge. The part behaves predictably under those conditions, so the waveform of the surrounding circuit stays as designed.
• Readable polarity. The white band on the black body shows which end is the cathode, so orientation can still be checked once the module is potted or the chassis is crowded.

Operating Media & Heat Path

• Insulating oil (recommended). Oil immersion gives a high voltage rectifier diode the strongest dielectric surroundings available and carries heat away from the body at the same time. It is the usual choice for X-ray tanks and oil-filled assemblies, and it lets a compact part work in a compact tank.
• Insulating gas (recommended). Gas-filled housings suit high voltage diodes in builds that must stay dry and light. The gas has to be clean and dry, and the housing design has to keep the field away from sharp metal edges; settle the gas specification with whoever supplies the tank.
• Secondary packaging or potting. Potted modules give good dielectric strength but can trap heat around the body. Check the thermal conductivity of the compound, and leave the leads some free length so heat can escape instead of soaking back into the module.
• Exposed air with forced cooling. An air build is the hardest case. Air breaks down at lower stress than oil or gas, a small axial high voltage diode is more prone to discharge at the lead ends, and convection alone may not carry the loss away — add airflow and keep the assembly clean and dry.
• Insulated electrodes in air. For an exposed-air installation, terminate both ends with insulated electrodes. That controls corona at the lead tips and keeps the discharge path away from the body surface.
• Clearance and creepage. Judge the layout by the distance over the body surface and along the leads, not only by the gap through air. Longer lead runs and a stand-off from metal parts both raise the withstand of the finished assembly.
• Give the body room. Mount the part where air can move across it rather than under sleeving or inside a tight wire bundle; a diode that cannot lose heat will not hold its rating for long.

Specifications

Insulating Adhesive Selection

Mounting & Installation

1. Check the marking and read the part against your drawing before you form anything. Once the leads are bent, a wrong part is easy to spot but awkward to return to stock.
2. Bend the leads around a support so the bend sits away from the body. Repeated flexing at the seal can crack the molding, and a cracked seal is exactly where tracking begins.
3. Fit the axial high voltage diode so the body sits clear of metalwork, with the cathode end matching the layout and enough lead length left for a stress-free joint.
4. Solder with a short, controlled heat cycle and let the joint cool naturally. A long dwell on the lead conducts heat into the body and softens the encapsulant around the chip.
5. Support the body against vibration with a clip, a bracket or a bead of potting compound, so the leads are not the only thing holding the part in place.
6. Fit a high voltage rectifier diode of the same voltage class in the same axial construction, re-form the leads to the existing footprint, and keep the cathode orientation identical to the part you removed.
7. Check clearance to nearby metal and to the tank wall, confirm polarity and continuity, and run an insulation-resistance check before first power-up — the same final gate high voltage diode manufacturers apply before a module is released.
8. Record the solder lot, adhesive batch and date on the build sheet. When a module comes back from the field, that record is what tells you whether the diode or the process moved.

Replacement & In-Service Checks

1. Isolate the high-voltage side and discharge it, then prove the circuit dead. A rectifier in a multiplier string can hold charge long after the supply is switched off.
2. Read the marking and any ratings on the failed unit before it leaves the board, and note the circuit position. That note is what you cross-check against when the replacement is ordered.
3. Look at how it failed. A cracked body, a scorched lead and a discoloured adhesive each point somewhere different, and the pattern often matters more than the part number alone.
4. Desolder with just enough heat to release the joint, and lift the part by the lead rather than levering against the molding.
5. Clean the site and inspect the insulation surfaces for tracking or carbon. A blackened path will conduct again even with a new diode fitted.
6. Fit the same voltage class in the same axial construction, re-form the leads to the existing footprint, and keep the cathode orientation identical to the part you removed.
7. Re-apply the insulating adhesive, cure it, then run an insulation-resistance check and a low-voltage functional test before the assembly goes back into service.
8. Keep the removed part until the repair is signed off. If the replacement fails the same way, the two compared side by side usually point at the circuit rather than at the diode.

Ordering & Delivery

Every order starts from a specification, so have the numbers ready: the reverse voltage the diode has to block, the average forward current your load draws, the medium the part will sit in, and the quantity the build needs. If you are replacing an existing diode, send the marking from the old body together with your drawing, and our engineers will cross-check it against the 2CL2 series before anything is quoted. Price, lead time and payment terms are confirmed on the quotation for your quantity, along with whatever changes them — a larger batch, a specific test record, or a packing format your production line needs. Shipments go by international express, and we confirm dispatch details with you before the goods leave Anshan. Ask your sales contact about sample availability and about the documents your qualification file needs; the datasheet, the package drawing and the installation notes are part of the standard documentation, and any additional test data can be discussed with the order.

Technical Support & Model Matching

Selection starts with your circuit, not a catalogue number: tell us the working voltage, load current, switching frequency and ambient cooling conditions, and our engineers will match a model from our range and explain the margin left in the design. Each model ships with its datasheet, package drawing and installation guide, and we stay available for mounting and soldering questions, start-up checks and fault finding when an existing part runs hot or fails early. Orders run from about 7 days to 6 months depending on quantity, usually by international express.

FAQ