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  1. HarryA1

    DARKROOM TIMER V2.0A FOR PCB EXPOSURE BOX

    Can you connect a 240v buzzer to the relay and get what you need? I don't know the circuit so I can not help much. Perhaps someone more knowledgeable will come along. I would think that the lead from the mains/transformer to the relay would be from the lead that has the fuse and power switch on...
  2. HarryA1

    How is my schematic layout and design

    The LEDs flash alternating. The flash rate is determined by C1 and R4. There are online calculators for determining these values. Just supply power for the hazard signals. Supplying power and disabling one or the other LED for the turn signal.  Redraw the circuit with circuitlab  and add a DPDT...
  3. HarryA1

    How is my schematic layout and design

    You should draw the fuse F1 as a blown fuse, you have a short circuit by the wire/conductor on the right. That was a test right? To see if anyone really looked at it 😉   Isn't the 7805 a voltage regulator? Not a flasher? What are the" flashers" connected to? Shouldn't they connect to the anode...
  4. HarryA1

    In the bowels of: TV IR Sensor

    In the photography is the remote control receiver module from a VIZIO television. At the lower center is IR sensor and to the right of the sensor marked by red is the power on white LED. This photography shows the output from the module  when a remote control button is pressed and held. The...
  5. HarryA1

    In the bowels of: LED tube lamp

    The photographs show the working end of a 24 inch LED tube light. This type of light only requires connections to one end. No ballast is required for this light. The light yellow device at the lower right is the transformer. Next to it is a yellow capacitor. On the bottom the larger three...
  6. HarryA1

    In the bowels of: Laptop battery

    For those who have not peeked in to a laptop battery the photo shows the interior of one. The battery is made up of 6 lithium ion cells of 3.7 voltages each in three pairs. Connected to each pair are connections for balanced charging. This battery does not have thermistors for monitoring...
  7. HarryA1

    In the bowels of: gas range

    For you folks that have not worked on a gas range /kitchen cook stove. In the photo the igniter at the top draws current through the gas valve below. The igniter draws current slowly at first as it heats up to typically 3.5 amperes. Only then does the heater (white windings) in the valve heat...
  8. HarryA1

    Help request about an optimum switching design

    There are only 6 unique numbers in each column  above. If you used 4 rotary switches with one wafer each that would only require 6 * 4 = 24 contacts. A 6 position switch with one wafer:
  9. HarryA1

    Help request about an optimum switching design

    I do not understand enough what you are doing to be helpful. Can you say, as a model, each electrode is like a wire of different metal (like copper, zinc, iron, etc) placed in an solution such that each creates a different  electromotive force (emf) or voltage. Each wire/electrode has a higher...
  10. HarryA1

    Help request about an optimum switching design

    You need to define " driven electrodes ". Are they two leaded devices? Can they share a common ground? Do you have  a set of relays in mind? If so can you use solid state relays?
  11. HarryA1

    Looking for a good design for a PIC based VU Meter

    Sorry I can not help you with the PIC; I use the Arduino myself. But there is a lengthy discussion of 4 pages related to the PIC  and VU meters here: https://groupdiy.com/index.php?topic=43594.0
  12. HarryA1

    need help designing relay circuit

    I would think replacing the relays. You can get a pair of Omron 24 VAC relays for  11$ off Ebay. Omron has a good rating on Amazon.com Else you can use a bridge rectifier to convert to cleaner (less ripple) dc. Search for "bridge rectifier diagram" for many diagrams on the  internet. A package...
  13. HarryA1

    variable square wave 100 volt 50 amp power supply

    That sounds like a major project. One would want to use a microcomputer as it would  simplify the circuitry greatly. Example: https://www.youtube.com/watch?v=9IWWa0xCd04&feature=emb_logo It is said that power supplies are less expensive today for EDM machines, perhaps you could search on...
  14. HarryA1

    SUBWOOFER COOLING FAN VARIABLE OPERATION

    I would think that is a good solution. A more elegant solution would be to use a temperature control switch in series with the fan. They are not very expensive.  You want one for example: less than 25 degrees normally open and higher than 25 degrees normally closed...
  15. HarryA1

    Motor driver JYQD_7V.3E3 24Volt datasheet (new version)

    You can download the data sheet from here but it  contains little useful information and the diagram is  not the correct one. http://www.bldcmotor-driver.com/sale-11494096-500w-brushless-dc-motor-driver-hall-effect-24-volt-dc-motor-speed-controller.html the link is near the bottom of the ...
  16. HarryA1

    Motor driver JYQD_7V.3E3 24Volt datasheet (new version)

    By pads do you mean the pads (marked hall) on the lower right of the board? If so knowing any dimension on the board, like a component, one can find other dimensions using a tool like photoshop or the poor man's version THE GIMP. Also knowing the board is 63x42.5x17 mm (L*W*H) one could scale...
  17. HarryA1

    Motor driver JYQD_7V.3E3 24Volt datasheet (new version)

    Searching for: JYQD-V7.3E3 on Yahoo  will give you a few  hits. Not  _7V good luck
  18. HarryA1

    CLOSED LOOP ANALOG DC SERVO MOTOR DRIVER

    The LMD18200 is rated 3 amperes and 12 to 55 volts: https://www.electronics-lab.com/project/lmd18200-h-bridge-module-for-dc-motor/
  19. HarryA1

    Intelligent power switch ESP32

    The IPS6021 is readily available from China via Ebay.  There is a supplier in the UK also: https://www.ebay.com/itm/IPS6021RPBF-Intelligent-Power-Switch-High-Side-Active-High-1Output-5-5V-TO-252-5/152755283380?hash=item2390eca5b4:g:U~MAAOSwqXxdNtVK 
  20. HarryA1

    MOSFET FAILURE

    Can you add a heat sink to the transistor - is there enough room for it? A 30 ampere transistor needs a good heat sink bolted to it.. Also you need  heat sink compound/paste/grease to get good thermal bonding.
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