Oven like OCXO for custom device - Page 1
Forum section: electronics / general

author: current-hunter
author_rank: Newbie
timestamp: August 22, 2023, 09:39:11 am
content: Hello,does anyone know if there is a oven (temperature controlled) for a custom device like resistor in the typical size of an OCXO available, please?Regardscurrent-hunter

author: iMo
author_rank: Super Contributor
timestamp: August 22, 2023, 11:08:02 am
content: FYI - here is an oven I salvaged from a perhaps 50-60y old ocxo. Controlled by32 transistors, 5 resistors and a thermistor (transistors and the thermistor embedded into the aluminum) and a resistive wire (50ohm) wound around the container, milled inside such it got place for the crystal and a small board with the oscillator.. 15V/0.29A cold and ~30-40mA when hot. I set it for 40C.Waiting on its reference..Edit: only two transistors and a zener (for stabilizing the bridge voltage in the original, I replaced it with a 78L08 I had handy).Below the schematics with a SIM - the real hw follows the sim almost perfectly..

author: Andreas
author_rank: Super Contributor
timestamp: August 22, 2023, 11:29:32 am
content: Hello,buy or make that is the question.perhaps something like this?https://www.kuhne-electronic.de/kuhne/de/shop/zubehoer/quarzheizer/2+x+QH+40+A++Praezisionsquarzheizer+40%C2%B0+QH40A/?card=1966#_tab_content1But the price tag increased since I bought my heaters at the "UKW-Tagung" some years ago.with best regardsAndreas

author: artag
author_rank: Super Contributor
timestamp: August 22, 2023, 11:57:15 am
content: You don't necessarily need heaters. If the case is sufficiently conductive to spread the heat around (as with the milled box iMo describes) then a power transistor can be a heater as well as the control device.Maybe a device such ashttps://www.st.com/resource/en/datasheet/tsm103w.pdfcould provide most of the rest of the circuit.

author: current-hunter
author_rank: Newbie
timestamp: August 24, 2023, 11:22:07 am
content: Thanks for your information.Is a pity that there is no out of the box solution available.Using a commercial temperature PID will result in a huge enclosure.Regardscurrent-hunter

author: bnz
author_rank: Regular Contributor
timestamp: August 24, 2023, 03:11:48 pm
content: Meerstetter has drivers for peltier elements or resistive heaters, e.g.:https://www.meerstetter.ch/products/tec-controllers/tec-1092They claim they are good for 0.01° stability.

author: hgl
author_rank: Regular Contributor
timestamp: August 25, 2023, 08:22:38 pm
content: I still have boards from OCXO heaters.Temperature adjustable via resistor approx. 50 - 100°C.The heating surface is 13x 10mm.More details and pictureshttps://www.mikrocontroller.net/topic/386300

author: TimFox
author_rank: Super Contributor
timestamp: August 25, 2023, 08:28:06 pm
content: Here's an article from the amateur radio fraternity on home-made "crystal ovens", one large enough for the oscillator, the other smaller.https://www.qsl.net/m0ayf/Crystal-Ovens.html

author: dietert1
author_rank: Super Contributor
timestamp: August 27, 2023, 11:02:26 am
content: These are very simple circuits. They do not implement linear (PI = proportional + integrator) control, but oscillate like a refrigerator (On-Off).An analog PI controller will need an integrator cap, so it may be a little bigger. Anyway, for a DIY oven, one would certainly make it bigger in order to keep the whole circuit at constant temperature (like oscillator in case of OCXO). Also the temperature controller should be inside the oven.Regards, Dieter

author: eplpwr
author_rank: Regular Contributor
timestamp: August 29, 2023, 04:29:24 pm
content: DigiKey has crystal ovens for TO-5/TO-39/TO-99 sized components, search for M051565. Unfortunately, the prices have increased 150% since I ordered some M05-series ovens back in 2021. Also MOQ used to be 1, now it is 100 for most models.If you want to make your own miniature circuit to fit the above ovens, there are component bases at:https://www.surplussales.com/ComponentBase/ComponentBase.htmlThe description says "TO-5 component base", but since it has 8 legs it's more like a TO-99.BTW, Surplus Sales also has LT1013ACH, usable for voltnuttery. I have no affiliation with them, just a happy customer.

author: alligatorblues
author_rank: Regular Contributor
timestamp: September 14, 2023, 12:11:37 am
content: I'd just use a transistor and thermistor.