Path: csiph.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Reinhard Zwirner Newsgroups: sci.electronics.components Subject: Re: Question regarding the identification of a component Date: Wed, 10 Sep 2025 19:06:23 +0200 Lines: 57 Message-ID: References: <68c0533e$4$10368$882e4bbb@reader.netnews.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Trace: individual.net TxPoEa6O1Pt8DIL3MJAL2wXpv6vqTanjK6DZUs+rcj6lM= Cancel-Lock: sha1:mJNOgbIv8e86OyojwxpTKPxgL2o= sha256:mHd8a+9kQQnXx8kYS0uFJ+seK4gDbllE7U+DvXKbjbY= User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0 SeaMonkey/2.53.21 In-Reply-To: Xref: csiph.com sci.electronics.components:6599 chrisnd@privacy.net schrieb: > On 10/09/2025 16:38, Reinhard Zwirner wrote: >> chrisnd@privacy.net schrieb: >>> On 09/09/2025 21:12, Reinhard Zwirner wrote: >>>> bitrex schrieb: >>>>> On 9/9/2025 8:38 AM, Reinhard Zwirner wrote: >>>>>> Attention: fup2! >>>>>> >>>>>> Hello, >>>>>> >>>>>> In an older power supply unit for GM counter tubes, the high >>>>>> voltage >>>>>> (max. 1 kV) is generated by a normal push-pull voltage converter >>>>>> (switching frequency approx. 8 kHz). In the HV filter chain, this >>>>>> >>>>>> >>>>>> >>>>>> capacitor is connected in parallel with the following strangely >>>>>> marked component of the same size, >>>>>> >>>>>> >>>>>> >>>>>> which my Far Eastern multitester identifies as an 8 nF capacitor. >>>>>> That could well be the case, but why the strange marking? A VDR? >>>>>> What >>>>>> do you think? >>>>>> >>>>>> Many thanks in advance for your hints. >>>>>> >>>>>> Best regards >>>>>> >>>>>> Reinhard >>>>> >>>>> Maybe "41C" indicates the transition temperature for a PTC? >>>> >>>> The part behaves in no way as sort of resistor. >>> >>> Unless it has failed, open-circuit? >> >> Yes and no. Multitester says: 7,8 nF capacitor. But a capacitor >> should just be open circuit, otherwise it's broken. On the other hand >> I doubt that a PTC/NTC is connected to ground and a 1 kV line. > > Sorry, I was still in VDR territory when suggesting open circuit. Don't worry! I just referred to the above mentioned PTC. I just tested a S20K300 varistor manufactured by EPCOS in series with a 33 k resistor: limiting startet at approx. 420 V, max. voltage across this varistor was about 460 V. (Multitester said: 820 pF capacitor ...). So I think an "open circuit" test result doesn't prove a 3 kV varistor is broken: my test voltage is limited to "only" 3 kV ... Regards Reinhard