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russian semiconductor convertion
Figure 2 was used to substitute letter K, to distinguish mill tec specs and more strict QC against general purpose devices. 3102/7 series are considered as universal npn/pnp BJT's...
Saturday, 20 January 2018 - 22:33
Device Signature 0x000000 Bootloader Atmega 1284P
perhaps this may put some light on the issue:  
Tuesday, 7 November 2017 - 22:30
Transistor failure in switching circuit even with freewheel diode
"N-FET but was unable to find the one with given constraint of Vds<=200mV at Id>=70mA." IIRC most custom LED torch drivers use mosfets that meet the criteria: operating from...
Wednesday, 25 October 2017 - 08:32
Transistor failure in switching circuit even with freewheel diode
Should have been posted in general electronics, but anyway. Vce when saturated can reach 0.3V according to the datasheet.   This leaves too little voltage for the relay...
Tuesday, 24 October 2017 - 10:01
Switches across uC pins
" the switches have a really high resistance when pushed but it doesn't seem to be a problem with the mute button" Methinks this is a combo of switches which are shortening a...
Wednesday, 8 March 2017 - 09:02
Simple oscillator for 1.7MHz piezo
Most of similar circuits incorporate capacitor (22.47 nF) in series with transducer.   Methinks worth trying, as well as different transistors.  
Thursday, 3 November 2016 - 21:16
Why doesn't the thermocouple work correctly?
Rohalamin wrote: 1. I desoldered the handle(its terminals) from the board and plugged in the board and measured the voltage of the pads that I solder the terminals of the handle...
Friday, 26 August 2016 - 20:14
Why doesn't the thermocouple work correctly?
Wash thoroughly the PCB from any residues of flux and dirt, check empty PCB for integrity. Double check passives, especially C19. Swap semiconductors and opamp to the new ones....
Thursday, 25 August 2016 - 15:30
Why doesn't the thermocouple work correctly?
If I am getting the point, both DMM and circuit red 0..3mV instead of 0..9mV. Would assume   thermocouple is a culprit then.  Would run a test with a separate...
Wednesday, 24 August 2016 - 19:47
Torby uses a breadboard?
To Jim: RS delivers has it, see http://RS Pro LED Headband Magnifier Kit - 1.2, 1.8, 2.5, 3.5 x. Can't find out if they operate in the US. OEM product for sure, branded as RsPro....
Wednesday, 24 August 2016 - 19:23
Why doesn't the thermocouple work correctly?
T12 have thermocouple in series with the heater with a voltage of around 9mV at 450 degrees Celsius. Perhaps reference to the " heat to the tip" applied in terms of temperature...
Monday, 22 August 2016 - 09:48
How this power supply work?
Looks like a flyback with weak regulation. Power Integrations offers  nice suite for supply design. PI chips have nice protection features. IMHO easier and safer than...
Sunday, 22 May 2016 - 18:33