Search results

Search Forums New Posts
  1. D

    Looking for an old Motorola IC OpAmp SC9533P (7308)

    Its got a heat spreader in lieu of 6 pins in the middle. a power opamp ? Might have been a stamp off part number for Grundig. Regards, Dana.
  2. D

    Varistor? Help ID Component

    If you take a well focused pic of it and do a image search using google you might be able to find it. Regards, Dana.
  3. D

    GCSE homework

    A representative look at transistor saturation : The "classic" rule of thumb to sat a transistor is to force Icollect/10 or more into the base. This is called forced beta in the industry jargon. But its a rule best used by examining the datasheet for sat behavior. You can see here if Ic = 1A...
  4. D

    What microcontroller is used in the car key? Why is the power consumption so low?

    Self discharge in a coin cell ~ 1% / year...... Hibernate modes in todays processors in 100's of nA current....stop mode in 10's of nA...
  5. D

    Mosfets as voltage dividers.

    One way of doing it is a front end to a bare power supply ...
  6. D

    Attiny1606 burning out when controlling a drv8251

    Input 1 and 2 of DRV8251 have 100K ohm pulldowns. So 1 K from ATTINY dominates the logic level on pin. You have the ATTINY85 pin configured properly ? Strong drive.....config. Regards, Dana.
  7. D

    Drier Startup Issue

    For current and voltage you want isolation measurement for safety. https://www.ti.com/lit/slyy154 Regards, Dana.
  8. D

    circuit breaker alarm

    A buzzer is typically piezo or magnetic. Drive circuits for both different. Piezo presents a ton of C to opamp output, which can cause its own oscillation independent of what you think the OpAmp inputs are doing due to stray C. In both cases you can get some HV or high current transients...
  9. D

    Drier Startup Issue

    Why not use a super cap battery bank on input side of inverter ? https://www.amazon.com/s?k=super+capacitor+board&crid=3N3E68JYT6HP4&sprefix=super+capacitor+board%2Caps%2C144&ref=nb_sb_noss_1 Not a designer in this area, so I may be way off base. Can you capture a graph of startup current and...
  10. D

    Attiny1606 burning out when controlling a drv8251

    I cannot find the max injection current permitted in Atmel parts to prevent triggering the parasitic SCR structure that is a part of the GPIO port pin inherent in all non isolated CMOS parts (pretty much all standard CMOS). This will cause latchup in a CMOS part if triggered, typically fusing...
  11. D

    Attiny1606 burning out when controlling a drv8251

    Is that a 1 ohm R between Attiny outputs and MOSFET gates ? Should me more like 20 - 50 ohms. Can you drive one of your mosfets with Nano and look at outputs of Nano with a scope, single shot trigger, edge detect, try both Vdd + .5 as a trigger and also Vss - .5 to see what transients you are...
  12. D

    ESP32 Audio Spectrum Display

    Excellent canonical design : Regards, Dana.
  13. D

    help peltier module

    Why reversing polarity ? You heating and cooling depending on a choice ? H Bridge is excellent way of doing polarity reversal. Or DPDT relay. What is the current needed for your Peltier ? How do you want to reverse polarity, a switch, temperature, meteorite impact.......? Are you planning on...
  14. D

    Can I remove DC motor driver's speed control potentiometer and drive it with microcontroller DAC output ?

    Post a pic of topside of board where one can read the part numbers. Can you find a schematic on web ? You are looking for a "Voltage to PWM" if your posted board has no PWM on it. And you have to match DAC range out to PWM range V input. Search Aliexpress using that term, many hits. This is...
  15. D

    pls help need to pass for my finals

    Controlling servo https://www.princeton.edu/~mae412/TEXT/NTRAK2002/292-302.pdf Button debouncing - https://www.eejournal.com/article/ultimate-guide-to-switch-debounce-part-5/ Regards, Dana.
  16. D

    Can I remove DC motor driver's speed control potentiometer and drive it with microcontroller DAC output ?

    That is a PWM controller, so question is does the pot a part of timing control on duty cycle or is it a V input to a PWM generator. Can you get a schematic of board and/or part numbers of ICs on board ? Regards, Dana.
  17. D

    Best way to put off Fire from a Mobile Robot

    You could always consider a hybrid power approach, bot seeks closest power connection, plugs itself in, and that provides power for pumps etc.. How did you determine you can get 200 feet ? Is there sunlight in some areas of warehouse ? How will you handle various suppression methods needed...
  18. D

    Magnetostriction.

    https://www.zaber.com/products/linear-actuators https://www.pi-usa.us/fileadmin/user_upload/pi_us/files/catalogs/PI_Catalog_Linear_Actuators_for_Precision_Motion_Control.pdf
  19. D

    I need help with this

    Basics. A micro with no non volatile memory (FLASH, in old days would have been EPROM or ROM) and with no volatile memory (RAM) must be provided with these external. So a memory map must be created, HW that differentiates from non-vol and volatile. The 8086 shares its address pins with both...
  20. D

    Make a 74LS193 Synchronous Down Counter Stop at Zero

    Take a look at this thread on topic of asynch clear and load related issues : https://www.electro-tech-online.com/threads/need-help-with-fixing-my-circuit-design.166016/#post-1450302 Regards, Dana.
Top