Oven controlled resistor article  - Page 1
Forum section: electronics / general

author: Overspeed
author_rank: Frequent Contributor
timestamp: January 03, 2025, 01:27:35 pm
content: HelloAn oven controlled resistor article , interesting , Isotech propose one also.Can be interesting to use affordable tempco resistors or use low value resistors as they have usually large tempco value.RegardsOS

author: dietert1
author_rank: Super Contributor
timestamp: January 06, 2025, 05:15:44 pm
content: Probably this serves as a first test. I can imagine some errors they don't consider in their paper:- Using one TEC only yields a setup with systematic temperature errors caused by a gradient along the device. In order to see the gradient one needs a second NTC sensor. One lesson i learned with this kind of setup: Don't log the temperature sensor used for the PID but a second one.- In their construct the gradient can be quite large as they integrated the banana sockets into the thermal structure. That means the temperature gradient will depend on what plugs/wires one uses with their device.- Their 1 Ohm resistor temperature behaviour indicates about 2.8 ppm/K which is a lot. I would try to find a better resistor to start with.- Another consideration is the thermal behaviour of their standard resistors when a test current is applied. I think that would be an interesting spec when everything depends on Millikelvin temperature deviations.Regards, Dieter

author: TimFox
author_rank: Super Contributor
timestamp: January 06, 2025, 05:20:43 pm
content: Your final lesson about using a second sensor is good advice for any feedback-controlled stabilization system.

author: iMo
author_rank: Super Contributor
timestamp: January 06, 2025, 05:21:34 pm
content: Hmm..

author: Jacques
author_rank: Contributor
timestamp: January 07, 2025, 02:42:02 pm
content: Looks to me like someone forgot a certain Greek letter (thermal EMF, current noise spec)...Edit: As an aside, I've wondered for some time why none of the usual suspects produce ovenized chip resistor networks. For example, something like the LT5400 with an integrated heater like one finds in some of the voltage references.

author: Overspeed
author_rank: Frequent Contributor
timestamp: January 07, 2025, 07:46:17 pm
content: Quote from: Jacques on January 07, 2025, 02:42:02 pmHelloCould be but all manufacturers need a market and if possible a market or mass production , bespoke products are $$$$ , as the IC with ceramic case rather epoxy or other limited market components.Other concern is the size now electronic go to ...micro sizeCould be possible to recycling a OXCO enclosure and install a resistor but resistor are quite big , another solution is to design a heating cap on TO-3 as they are supplied by VishayRegardsOS

author: dietert1
author_rank: Super Contributor
timestamp: January 07, 2025, 08:40:01 pm
content: With precision electronics it can be more efficient to have a thermostat for a whole circuit.I'm right now studying a thermostat for LiPeFo4 batteries, and it turned into a pretty complex setup with an outer TEC oven running at 22 °C and two inner heater ovens for the battery sets running at 23 °C. The outer oven has enough space to contain a large circuit, including voltage references, supply voltage regulators, battery chargers with PWM current control and the analog PID controllers for the two inner ovens. The circuit uses two 8x NOMCT resistor arrays.Only the two channel peltier controller and the power parts of the regulated supplies are outside.Regards, Dieter

author: Overspeed
author_rank: Frequent Contributor
timestamp: January 07, 2025, 08:50:02 pm
content: Quote from: dietert1 on January 07, 2025, 08:40:01 pmHelloI agree as resistor are not the only problem , other act as a ''kettle'' , transistor and Mosfet so they also need temp control.Perhaps a gaming computer as Watercooling - CORSAIR - H100 RGB AIO can be a nice base ? no electrical wiring inside the temp controled enclosureRegardsOS

author: mendip_discovery
author_rank: Super Contributor
timestamp: January 07, 2025, 09:53:34 pm
content: Quote from: Overspeed on January 07, 2025, 08:50:02 pm