Simple, no-math transformer snubber using Quasimodo test-jig

Jump to Latest
#382
Using 15VDC to supply Quasimodo, attached infinityR
 

Attachments

  • WP_20140911_001[1].jpg
    WP_20140911_001[1].jpg
    330.3 KB · Views: 683
Last edited:
#390
... when Quasimodo operates the LED is intermittent shine & not shine but when operates certain time the LED don't shine ...
Click to expand...

Your Quasimodo v.4 is broken. Here is the relevant portion of its schematic; D2 is the LED. D1 and D3 are protection diodes which prevent overcurrent if someone connects the power supply backwards.

As you can see, there is a pure DC current path (red arrows) from PWR_IN to GND which flows through the LED. The path is
  • P1 (external I/O pin) receives PWR_IN from power supply
  • D1 Anode
  • D1 Cathode (node name: VCC)
  • LED Anode (node name: VCC)
  • LED Cathode
  • 820 ohm resistor R1
  • GND
  • P3 (external I/O pin) receives GND from power supply
A pure DC current flows through the LED, its value is (Vsupply - (VD1 + VLED)) / 820 ohms . When you drive a standard LED with a pure DC current, it emits a continuous beam of light of constant, non-varying illumination.
 

Attachments

  • QM_v4_LED_ckts.png
    QM_v4_LED_ckts.png
    9.9 KB · Views: 419
You must log in or register to reply here.
Top Bottom