Search results

Search Forums New Posts
  1. AnalogKid

    Timer circuit

    There is nothing wrong with your reset approach. Just because it is not all solid state, that doesn't make it "crude". If it already is built and works, there is no automatic reason (inability to get parts, long term reliability, etc.) to change it. BUT - that relatively gigantic timing...
  2. AnalogKid

    Timer circuit

    Yes, there are two or three modifications to the standard timer circuits that will reduce this problem, but without knowing the circuit he is using it is just random speculation. ak
  3. AnalogKid

    Driving a piezo buzzer: resultant tone is noisy. Why?

    A 1-opamp phase-shift oscillator circuit and a single-chip audio power amp will get you a nice, clean sinewave that will drive the piezo without kicking up harmonics. Distortion can be under 2-3%, and the frequency is tuneable over a narrow range with a single pot. ak
  4. AnalogKid

    Timer circuit

    Please post your schematic. It might be possible to solve your problem with a circuit modification. Please post your schematic. Think about the question you are asking. Please post your schematic. ak
  5. AnalogKid

    Arduino reading double-din radio volume rotary dial knob

    Disagree. A rotary encoder is not an active coomponent, and does not have 5 V and GND pins. It is two concentric rotary switch patterns. The three contacts are common, phase A, and phase B. The A and B patterns are 90 degrees out of phase. A common interface is to connect the common pin to...
  6. AnalogKid

    Circular?

    PADS (now a part of Mentor) allows irregular pcb outline shapes, including circles, obrounds, etc. Internally, it is the same closed line engine that is used for copper pours. ak
  7. AnalogKid

    Op amp problem ua741

    The datasheet for the 741 lists its capabilities. In both tables and plots it shows the output voltage swing range. If you don't know how to interpret the datasheet, post a PDF of the one you have (there are many different versions from many manufacturers) and we can explain exactly where the...
  8. AnalogKid

    Old School House Wiring

    Yes, a *huge* one. Remember, UL was formed by a group of insurance companies to deal with the large number of - wait - electrical fires caused by cotton (!!!) insulation. A friend had to have her whole house re-wired. That was the easy part. The hard part was the requirement to *remove* the...
  9. AnalogKid

    falstad

    The most popular circuit simulator is (free) LT Spice, published by Linear Technology (now owned by Analog Devices). Component libraries, design libraries, the whole works. And many LT app notes come with Spice design files already created to drop in and modify. linear.com ak
  10. AnalogKid

    What's the name of this circuit?

    That circuit is called a common emitter amplifier. The single resistor to the base is called dangle-biasing. ak
  11. AnalogKid

    RS232 - RS422 CONVERTER

    For point-to-point connections (non-bused), 422 and 485 are essentially identical. 422 allows multiple receivers on one line, but only one driver. 485 allows multiple drivers and receivers on one line. ak
  12. AnalogKid

    Having trouble building circuit?

    If there are no voltages on either of the 555 capacitors, then the 555 has no power applied to it. Pin 5 should read a constant 1.67 V. The other end of each capacitor is connected to GND, so there will no voltage reading there. ak
  13. AnalogKid

    RS232 - RS422 CONVERTER

    I know that part. But I can't seem to hit the right combination of words to have that part come up in a general search. For example, changing from "RS232-RS422" to "RS232 to RS422" got me closer, but your part still did not come up. Not exactly the end of the world. ak
  14. AnalogKid

    RS232 - RS422 CONVERTER

    You're right, same thing, better price. Don't know why that one didn't come up in my search. https://www.ebay.com/itm/RS232-to-RS485-RS422-Serial-Data-Converter-and-Terminal-Board/132383914970?hash=item1ed2b23bda:g:LRYAAOSwPPpaQe-K Similar item, different company, Still can't get Minder's to...
  15. AnalogKid

    RS232 - RS422 CONVERTER

    https://www.ebay.com/sch/i.html?_from=R40&_nkw=RS422-RS232+converter&_sacat=0&_sop=15 https://www.ebay.com/itm/RS-232-To-RS-422-RS232-To-RS422-RS-232-To-RS-422-Converter-Adapter/171966151277?hash=item2809fb3a6d:g:64EAAOSwFL9Tvfx8 I'm not wild about this device getting its operating power from...
  16. AnalogKid

    Having trouble building circuit?

    Disagree. Sloppy construction is a choice. ak
  17. AnalogKid

    Having trouble building circuit?

    No. Is the circuit running too fast? Too slow? Did it burst into flames? Think about it - do you really believe that "I'm having trouble" is actual information? However, the construction does need help. Add a ceramic decoupling capacitor across the power and ground pins of each chip. Keep...
  18. AnalogKid

    Capacitor charging

    A 555 monostable circuit is not a "true" monostable because it does not have positive feedback to make the output pulse width independent of the input state after it is triggered. It also is not a normal retriggerable monostable, because if it receives a 2nd trigger input before the first...
  19. AnalogKid

    Live Audience Response System

    I'm leaning that way also. Multiple-choice makes it a bit more messy, but a party-line system is way less complex than 300 individually addressable items to poll continuously. Cat-5 cable is cheap, relatively reliable, and has 8 wires. That's power, ground, 5 analog outputs, and one reset...
  20. AnalogKid

    2 transistors as SPDT?

    1. This thread is over 5 years old. 2. This can be done with no transistors at all: 1 resistor to limit the current to *both* LEDs 1 small diode 1 SPST switch ak
Top