Maybe testing the µcurrentsOr maybe he's testing the new and completely revolutionary no-prefix-current, which can measure currents in the range 1 mA - 10 A. Just like with the µCurrent, the user can plug in a test current on one side and get a voltage reading on the two other terminals, with the scale 1 V/A. I hear the no-prefix-current features a passive design, which has a heavily reduced complexity compared to the µCurrent and doesn't even require a battery.
I had built multi-channel current loads, even with simple LM324 usually things work pretty okay, but to be exact, i was using NFETs (IRF3205 for "low" power channels 0-30A and FB180SA10P for 0-50A). I was doing that for computer power supply ATE, driving 12 channels from 8bit DAC. Caps and proper passives are critical tho, but even on breadboard all should work fine.
Maybe testing the µcurrentsOr maybe he's testing the new and completely revolutionary no-prefix-current, which can measure currents in the range 1 mA - 10 A. Just like with the µCurrent, the user can plug in a test current on one side and get a voltage reading on the two other terminals, with the scale 1 V/A. I hear the no-prefix-current features a passive design, which has a heavily reduced complexity compared to the µCurrent and doesn't even require a battery.
Dave: I think a bypass cap between the force and the sense pins should do the trick. (The control loop becomes unstable because the transistor is to slow.) I've tried it in the simulation provided by Jay_Diddy_B and it seems to works there:
Try substituting the ceramic caps for electrolytics, or add a very small series resistance (0.5-1R) in series with the ceramics. Sometimes their ESR is TOO LOW, forms an underdamped LC tank circuit with the PCB trace/wire/package/whatever inductance, causing ringing on transients and oscillation.
Dave butchery with poor TSSOP. Need some TSSOP-8 adapters? We have plenty of them here in Taiwan on local radio hobbyists shop.
P.S. Long time wanted ask you, from previous videos you have all nice gear, Agilent scopes, but mostly using Rigol gear. Why so, is there some deal with vendor, so u tied to that when doing videos? I'd use best available tools for experiments, if there is a choice. Just curious..
Hmm, at the risk of appearing to give up on the LTC6655 device a little early, what about the MAX6225? I have a couple of these rigged as precision and untrrimmed voltage references. They are ROCK STEADY even on a breadboard, AND are available in good 'ole 8 pin DIPs
P.S. Long time wanted ask you, from previous videos you have all nice gear, Agilent scopes, but mostly using Rigol gear. Why so, is there some deal with vendor, so u tied to that when doing videos? I'd use best available tools for experiments, if there is a choice. Just curious..
Dave: I think a bypass cap between the force and the sense pins should do the trick. (The control loop becomes unstable because the transistor is to slow.) I've tried it in the simulation provided by Jay_Diddy_B and it seems to works there.
Once again. The oscillations may be caused by the SPICE engine in LTspice and not the circuit topology itself. Try this:
Hello Dave - I am interested to know where you source those little SMD breakout boards from on which the LTC6655 was soldered ?