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My question is very simple. What components should be removed from the following circuit diagram for this circuit to work only on DC voltage? I'm sure that the bridge rectifier should be removed further than that I do not know.Circuit Diagram

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  • \$\begingroup\$ Welcome to EE.SE! Your question is far from simple. What does it do? What does work mean? What is the expected behavior after modification? \$\endgroup\$ – winny Sep 3 '18 at 10:09
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You can remove everything connected to pin 16, VCC, which is where your DC power will go.

Although, depending on your DC source, you may need a filter capacitor. So, leaving C12 would be a good bet.

If you want to keep the LED power indicator, do so, but you may need to adjust the resistor (R5) value depending on your DC voltage.

From the datasheet it looks your DC supply voltage should be between 3 and 15 V.

And, of course, you might want to keep the power switch.

Basically, placing your DC supply at pin 1 of the switch, would probably work fine (after verifying that the LED resistor is suitable).

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  • \$\begingroup\$ As far as I understand, everything needs to be removed from the pins 16 but the C12 capacitor, and what value is R5 fo 15V? \$\endgroup\$ – Smekeri BezPrezimena Sep 3 '18 at 10:14
  • \$\begingroup\$ You can keep R5 as it is. 15V/1000Ohm = 15mA, so there will never be more than 15mA passing through the LED. Common LEDs are specified for 20mA, and you have some drop across the LED (2-3V depending on color) so you can assume the current to never be more than (15V-2V)/1000Ohm = 13mA which is fine. \$\endgroup\$ – JimmyB Sep 3 '18 at 10:32
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Why remove any components? It'll work on DC just fine without any component removals and you won't need to worry about someone putting DC onto the circuit with the wrong polarity because the bridge will protect against reverse polarity.

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  • \$\begingroup\$ Because for this circuit needs to be transformer, someone can not get a transformer. That's why I asked the question of what needs to be removed to work only DC voltage. \$\endgroup\$ – Smekeri BezPrezimena Sep 3 '18 at 10:33
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    \$\begingroup\$ @SmekeriBezPrezimena Andy is saying you don't need to remove anything, just connect the DC where the AC currently goes. \$\endgroup\$ – Colin Sep 3 '18 at 12:35

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