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  1. Rleo6965

    Heat Issues with LM732 Power Supply

    To avoid too much heat or voltage drop on 2N3055 in DC output of 13V or lower. Design your power transformer to have secondary winding of 18VAC and 32VAC. Place a switch or relay to select 18V winding for +13V DC and the 32V winding for +24V DC output.
  2. Rleo6965

    What does the 33uH coil in this circuit?

    Let's say the base voltage was 3V and the emitter was 2V there will be 1 volt bias on transistor that transistor conduct will small current. But if you "pushed down" or lower the emitter voltage to 1V. There will be 2V bias between base and emitter. this therefore cause more current to flow on...
  3. Rleo6965

    What size cap do I need?

    Place the 12V regulator close to device or its load.
  4. Rleo6965

    Simpson 260 Series 5 Multimeter Repair

    I think analog meters have different DC voltage or Battery for Low and High range of resistance reading. It's also probable that shunt resistance for that range have changed value and needs replacement.
  5. Rleo6965

    Rs485 to Ethernet & ethe to rs485

    You can also use this. if your serial communication for hardware handshaking and faster baud rate.
  6. Rleo6965

    Rs485 to Ethernet & ethe to rs485

    Oooops. We use straight cable wiring for Micros POS System only. You need to use cross wiring configuration with RS485 cable and use twisted pair for pin1 & 2 and other pair for pin 3&4. . Pls see attach picture for RS485 and RS232 cable You can use straight cable for ethernet Moxa connection...
  7. Rleo6965

    Rs485 to Ethernet & ethe to rs485

    Most probable that cable configuration of Ethernet cable between Moxa 5430A and Moxa 5130A will straight cable or pin1 to pin1 etc. This is also same with RS485 cable between Moxa 5430A and Moxa RS485 to RS232. For the RS232 cable for PC and MY BOARD, we need serial port pinout configuration...
  8. Rleo6965

    how the circuit work!

    It look like will not oscillate at all and the electrolytic was too much capacitance for a 300mhz oscillator. If it oscillate.
  9. Rleo6965

    New Power Supply

    Do you really need sw1 and R2 5 ohm 5w resistor? It's connected as shunt resistor to 48V output of bridge rectifier. Surely your R2 will go to smoke and also damaged your power transformer due to high current.
  10. Rleo6965

    New Power Supply

    I can't find current limit circuit on voltage reg U1 and U5. What's the function of 2 pcs LM317 U2 and U4. It look like constant current load for the power supply not current limit. This will make your power transformer and transistor hotter.
  11. Rleo6965

    New Power Supply

    Was that "rule" for 60hz only? How about for 20khz inverter bridge filter capacitor? What will be the capacitance per 1 amp?
  12. Rleo6965

    Help asap

    4xxx cmos series ic needs pull-down or pull-up resistor to protect from static discharge sensitive unused input pins only. No need to place pull-up or pull-down resistor to protect output pins. If its really a "unused" input pin. You can directly connect to vcc or ground to protect it without...
  13. Rleo6965

    New Power Supply

    I think that series pass transistor in negative side must be pnp and its emitter must be connected to load side.
  14. Rleo6965

    Simple tach for my lathe

    You can also use mirror to reflect light signal to emitter and receiver diodes.:D
  15. Rleo6965

    NAD 7240PE Receiver "Idle current adjustment" manual clarification/help.

    I can't find the shorting etch across R471 from uploaded photo. . You can confirm if there's really a shorting etch across R471 by measure a 0 ohm resistance once R471 was unsolder or removed.
  16. Rleo6965

    NAD 7240PE Receiver "Idle current adjustment" manual clarification/help.

    This is the way I understand the instruction. Pls see portion of schematic diagram from your uploaded photo 7240 PE Schematic Up-right.jpg (4 of 5) The instruction was that you have to measure “reading of 28mV +/- 2mVDC”. This voltage was so low to measure on +43V supply rail. So, I think that...
  17. Rleo6965

    Circuit Simulator program request [HELP]

    Try circuit wizard. You can download free trial version. Here's their link: http://www.new-wave-concepts.com/downloads.html
  18. Rleo6965

    NAD 7240PE Receiver "Idle current adjustment" manual clarification/help.

    Pls. post picture of mentioned R471 and R472 pcb connection also include schematic diagram. Surely, we will able to help.
  19. Rleo6965

    Safety circuit PCB from a ride on mower

    That's very clear shot. Are you a professional photographer?
  20. Rleo6965

    Why AREN'T my fuses blowing?

    You might want to add current limit circuit to your 12V supply. 12V output will turn off if current flow reached the set current limit. This a fuseless solution.:)
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