Vijit Dubey
Member
I am still waiting for delivery for the RLC meter.any luck with my cct?
For the circuit you mentioned, I would need a high speed comparator. I tried with the normal one (we both knew it wouldn't work). I would get one soon.
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I am still waiting for delivery for the RLC meter.any luck with my cct?
Perhaps a tad late to suggest this, but...Let's say I have a capacitor and inductor (used in a tank circuit for induction heating application). It operates at a PLL using CD4046. However, to calibrate the starting frequency I must know the tank's resonant frequency. Using either a micro-controller or any other logic, what would be the best way to identify the tank's resonance frequency by sweeping from a high frequency in such a way that I get a number displayed as the resonance of the circuit.
You're right, of course. Low Q can result in little or no observable "dip". For sure if using a mechanical meter.Unfortunately Bob the DGDM is designed for high reactive impedance resonant coils that dip to much lower impedance such that it absorbs energy to dip the grip meter.
This external tank circuit has a reactance of <1 Ohm at resonance so it not not even close to be matched to the meter impedance and thus no variation in grid current can be seen unless it was digitized in parts per million.
This looks good in the simulation. Let me try to replicate this on my breadboard.No hysteresis,, negative feedback becomes a voltage follower
https://www.falstad.com/circuit/circuitjs.html?cct=$+2+1e-8+105.18789638808724+1+5+50 r+512+328+512+376+0+33000 c+720+168+720+224+0+1e-7+1.7647368916329036 w+472+136+472+184+0 w+472+136+720+136+0 w+696+72+720+72+0 w+720+224+672+224+0 w+696+104+696+72+0 w+672+224+672+200+0 w+528+184+528+216+0 g+672+224+672+248+0 w+672+168+720+168+0 w+648+360+648+320+0 R+720+72+720+32+0+0+1+5+0+0+0.5 183+528+184+584+184+0+0.5+1.66+3.33 w+720+136+720+168+0 a+648+368+720+368+3+5+0+1000000 t+640+184+672+184+0+1+-1.7647368911329036+4.999999998019801e-10+100 r+640+184+584+184+0+10000 183+472+184+528+184+0+0.5+1.66+3.33 w+584+184+584+216+0 174+720+72+696+136+0+2200+0.41090000000000004+NTC+2.2+CMOS x+739+111+837+114+0+14+NTC+2k2@25'C r+512+416+512+376+0+10000 g+512+416+512+440+0 w+512+376+648+376+0 R+512+328+512+288+0+0+1+5+0+0+0.5 c+456+376+456+416+0+1e-8+1.1627906976732851 w+720+320+848+320+0 w+512+416+456+416+0 w+456+376+512+376+0 x+867+295+965+298+0+14+NTC+2k2@25'C 174+848+256+824+320+0+2200+0.5891000000000001+NTC+2.2k+OPAMP t+768+368+800+368+0+1+-1.7244751883959766+-8.996682471329543e-7+100 w+848+320+848+352+0 R+848+256+848+216+0+0+1+5+0+0+0.5 w+800+352+848+352+0 g+800+408+800+432+0 w+800+408+800+384+0 w+824+288+824+256+0 w+848+408+800+408+0 w+824+256+848+256+0 w+720+368+720+400+0 c+848+352+848+408+0+1e-7+1.7244742887277293 r+768+368+720+368+0+10000 r+648+320+600+320+0+10000000 r+720+320+648+320+0+3300000 g+600+320+600+344+0 c+600+280+648+280+0+1e-10+-1.1537890152019579 w+648+280+648+320+0 w+600+280+600+320+0 w+576+248+944+464+0 w+928+232+568+472+0 o+14+64+0+290+5+0.0015625+0+-1 o+8+64+0+298+5+0.00009765625+0+-1 o+19+64+0+298+5+0.00009765625+0+-1 o+26+64+0+290+2.5+0.00009765625+1+-1 o+41+64+0+290+10+0.00009765625+1+-1 o+42+64+0+290+5+0.025+1+-1
Edit Op Amp Voltage to +5, -0V
I tried with Op Amp but found simpler solution. It needs 2 stages to be high impedance and negative feedback with inverting Q to get hysteresis but negative feedback
( confusing but it ends up as Ramp Sweep pulse generator)
UPDATE.This looks good in the simulation. Let me try to replicate this on my breadboard.
Thanks.
What kind of alien technology is that?... circuit monitoring 4 IGBT thermistors ...
ff900r12ip4 IGBTs have thermistors connected to the cooling plate. I am using 4 such thermistors in a timer circuit to monitor temperatures and display on PLC.What kind of alien technology is that?
Specs of what?Will system response time protect IGBT's?
What is spec?
Specs for temperature accuracy , thermal resistance of Tjc to estimate junction temp, control system response to load control with dynamic loads (arcs)Tony Stewart
I ran it when load was 70% on a 300KW machine. Monitoring the thermistors of inverter IGBTs which are water cooled.
**broken link removed**
when no load is operated. there is no flickering of the frequency.
The thing is that looking at the difference between what simulation tells me and what I found was around 20 degrees but the difference between each temperature was almost similar. So, I am assuming it is due to resistances in the rest of the circuit. I right now used actual resistor(1/4 W) to come up with the green column and I am going to use this as a reference for my thermistor.I was wondering if you measured calibration error somehow.