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analog feedback temprature regulator question

yefj

New Member
Hello, I am looking for a differential feedback temprature regulator project which explains the theory best it could and give practical example in simulation.
I am looking to design a very precise temprature regultor up to 1Kelvin.
Is there some material of a project I could try to learn it?
Thanks.
 
Hello Dana,100Kelvin with 1Kelvin precision.
purely analog feedback ,is there some similar projects I could try to learn from?
maybe PID analog system?
 
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Consider using Wiki, GPT or Grok then verify sources from Mfg sites.

It is not called differential temperature regulator. It may be just an oven with a thermostat with 0.x 'C hysteresis or with proportional feedback.

(temp) some 4 syllable words do sound like 3.. and some people can make a 1 syllable word sound like 2.:joyful:

The thermal sensor needs specs for temperature range, voltage, current, response time and accuracy.

Temperature ranges affect the sensor choices such as a diode, NTC ceramics(Thermistor), RTDs, thermocouples and IC's that output 1mV/deg K (LM35)

I suspect you only need 1 temperature but need to learn about insulation and double ovens for tighter control using what you learned about thermodynamics.

For slow responses and large error tolerances +/-1 you may not need PID feedback rather just proportional error in a bridge with gain and calibration.
 
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Hello Tony, I saw a device in the lab which I was told using PID analog circuit to make a temperature in a box very very precise.
Do you have something similar I could learn from?
Thanks.
 
That is only true for the temperature of the sensor not the object being sensed.


The tolerance in selection is the initial error.
The accuracy is determined by traceable calibration.

Errors come from gradients inside the oven AND the part using, 1 sensor, 2 or 3?
Conduction, Convection heat flow or forced air? which is better?

"Do you have something similar I could learn from?"

Yes , search engine, Wiki , or AI or a book , depends on what need to learn.

SELF-HEATING is also a problem.
 
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e.g. Grok3

what is the best reference for oven control of a YIG RF OSC

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To determine the best reference for oven control of a Yttrium Iron Garnet (YIG) Radio Frequency (RF) Oscillator, we need a resource that combines expertise in YIG oscillator design, oven-controlled temperature stabilization, and RF performance optimization. YIG oscillators are specialized devices that use a YIG sphere as a tunable resonator, often requiring precise temperature control to maintain frequency stability, especially in high-performance applications like microwave synthesizers or test equipment. Since no single definitive "best" reference exists without context (e.g., your specific application or experience level), I’ll evaluate and recommend based on available knowledge and practical utility as of March 13, 2025.

Understanding the Context

YIG RF oscillators leverage the ferrimagnetic properties of YIG spheres, which resonate at microwave frequencies proportional to an applied magnetic field. Their frequency stability is sensitive to temperature due to thermal expansion and changes in magnetic properties, making oven control critical for applications needing low phase noise and wide tuning (e.g., 3–50 GHz). Oven control here mimics the concept of an Oven-Controlled Crystal Oscillator (OCXO), but adapted for YIG’s unique characteristics. The “best” reference should cover:
  • YIG resonator behavior.
  • Oven design for thermal stability.
  • Integration with RF circuitry.
  • Practical implementation details.
Candidate References
Let’s explore some strong contenders based on their relevance and depth:
1. "A Low-Noise Transmission-Type Yttrium Iron Garnet Tuned Oscillator Based on a SiGe MMIC and Bond-Coupling Operating up to 48 GHz" (IEEE, 2019)
  • Content: This paper details a modern YIG-tuned oscillator using a SiGe MMIC, focusing on low phase noise and wideband tuning (up to 48 GHz). It includes an equivalent circuit model for the YIG resonator and discusses thermal considerations implicitly through performance optimization.
  • Relevance to Oven Control: While it doesn’t explicitly design an oven, it provides measured phase noise and tuning data (-100 dBc/Hz at 10 kHz offset), implying stable temperature management. You’d need to infer oven specifics from stability requirements.
  • Strengths: Peer-reviewed, cutting-edge design, practical results.
  • Weaknesses: Lacks explicit oven control details; assumes prior knowledge of thermal stabilization.
2. Micro Lambda Wireless YIG Oscillator Tech Briefs
  • Content: Micro Lambda Wireless, a YIG component manufacturer, offers tech briefs on YIG-tuned oscillators. These cover magnet specs, RF performance, and power consumption, noting that YIG spheres perform best at constant temperature, often using a beryllium rod and heater.
  • Relevance to Oven Control: Directly addresses thermal management, explaining how a conductive rod stabilizes the YIG sphere’s temperature. It’s practical, not theoretical.
  • Strengths: Industry-focused, hands-on, includes specs (e.g., tuning range, power draw).
  • Weaknesses: Not peer-reviewed; lacks deep design equations or thermal modeling.
3. "Crystal Oven" and OCXO Literature (e.g., Electronics Notes, Wikipedia)
  • Content: General OCXO resources describe oven design for quartz crystals (e.g., AT/SC-cut), using heaters, thermistors, and PID control to maintain ±1×10⁻⁹ stability. YIG ovens adapt similar principles.
  • Relevance to Oven Control: Provides a foundation for oven design (e.g., 70–85°C setpoint for shallow frequency-temperature curves), adaptable to YIG’s higher Q and microwave focus.
  • Strengths: Broadly accessible, explains thermal control basics.
  • Weaknesses: Quartz-specific; no YIG context.
4. "YIG Sphere" and "Yttrium Iron Garnet" (Wikipedia, Microwaves101)
  • Content: These cover YIG’s properties (Q = 100–200, tuning via magnetic field) and applications (oscillators, filters). They mention thermal conductivity rods but not detailed oven design.
  • Relevance to Oven Control: Limited to noting temperature’s impact on resonance; no control specifics.
  • Strengths: Free, foundational YIG info.
  • Weaknesses: Too basic for practical oven design.
5. Hackaday’s "Inside A Vintage Oven Controlled Crystal Oscillator" (2025)
  • Content: Dissects a Toyocom TCO-627VC OCXO, revealing a heating coil and thermistor feedback. While not YIG-specific, it’s a teardown of oven mechanics.
  • Relevance to Oven Control: Shows real-world oven implementation (insulation, feedback), adaptable to YIG with adjustments for microwave frequencies.
  • Strengths: Visual, practical, recent (Feb 2025).
  • Weaknesses: Crystal-focused, not YIG; no design equations.
Evaluation and Recommendation

For oven control of a YIG RF oscillator, the ideal reference bridges YIG-specific RF needs with oven design principles. Here’s my reasoning:
  • IEEE Paper: Excellent for YIG oscillator design and performance but thin on oven specifics. Best for RF engineers already familiar with thermal control.
  • Micro Lambda Briefs: Practical and YIG-focused, with thermal hints (e.g., beryllium rod heaters). Ideal for implementation but lacks depth for custom design.
  • OCXO Literature: Robust on oven control (e.g., PID loops, thermistor placement), but requires adaptation to YIG’s ferrimagnetic behavior.
  • Hackaday: Hands-on, inspiring, but too general for YIG specifics.
Best Reference:
I recommend combining Micro Lambda Wireless Tech Briefs with OCXO design principles (e.g., from Electronics Notes or "Design and Implementation of Oven-Controlled Crystal Oscillator" on ScienceDirect).

Here’s why:
  • Micro Lambda provides YIG-specific context: how temperature constancy boosts Q and tuning linearity, with real-world hardware insight (e.g., heater integration).
  • OCXO Resources fill the gap with detailed oven design: heater power (e.g., 1–5W), thermistor feedback (e.g., NTC with 10 kΩ at 25°C), and stability specs (±20 ppb feasible for YIG with SC-cut-like care).
  • Why Not One Source? No single document I can access fully merges both, but this duo balances theory and practice. The IEEE paper is a close runner-up for advanced users, but its oven focus is indirect.
Practical Application

For your YIG RF oscillator:
  • Oven Design: Use a 70–85°C setpoint (common for shallow frequency-temperature curves), a small heater (e.g., 1W resistor or coil), and an NTC thermistor for feedback. Insulate the YIG sphere (0.5 mm diameter) in a compact enclosure.
  • YIG Integration: Mount the sphere on a thermally conductive rod (beryllium or copper), per Micro Lambda, to couple heat evenly while tuning via electromagnet (3–50 GHz range).
  • Control: Adapt OCXO PID logic (proportional-integral-derivative) to maintain ±0.1°C, achieving <1 ppm stability, better than a typical TCXO.
If you’re building this (e.g., for 27–31 GHz from your earlier question), simulate with ADS or HFSS using Micro Lambda’s specs and OCXO thermal models. Want me to sketch a basic oven circuit or dig deeper into a specific aspect?
 
Identifying the sources of heat and rate of change may require PID considering dynamic pulse powers and duty cycle, swell or duration.

Thus a heat bar for thermal mass makes sense but predicting self-heat may also be part of the equation.

The thermal network ends up looking like a network of series and parallel resistors with capacitors and regulating the voltage from all disturbances.
 
Although the application not refers to implementing PID control digitaly it gives the basic principle that can be applied when using op amps to implement it.
Les.
 
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