Increasing Current Capability of circuit

[liquidzell2]

Hello guys … I have a High Voltage Indicator and I am trying to find ways to increase the current capability in order to use it to have more “driving” power (to connect to something else) any ideas on components I can add to it (I don’t want to just reduce the resistance of the resistors) Thanks for any help!

 

[waross]

The two accepted ways to increase current through a resistor are to increase the voltage across the resistor or to reduce the resistance. This is not just a good idea, IT'S THE LAW (Ohm's Law)

Bill
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"Why not the best?"
Jimmy Carter

 

[Skogsgurra]

There is not only a LAW. There's also a recommendation about beating dead horses: DO NO DO IT!

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[DRWeig]

Yes, listen to Gunnar and Bill.

If you didn't like the answers in yesterday's post, well, eng-tippers are generally law-abiding people. We don't try to find loopholes Ohm's Law.

Since you don't want to decrease the values of R1 and R2, perhaps consider putting a much smaller resistor in parallel across both of them.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[Skogsgurra]

My wife adds: Do not beat live horses either!

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[liquidzell2]

Thank you.

 

[sunnysky]

Without PN's of LEDs and desired current peaks and averages, I can not give you precise answers, but it is not hard to see you are burning out your Cap charging resistors and creating a relaxation oscillator with negative rail DIAC in series with the LED string.

Unless you are trying to make a flashing high voltage LED array, I would stick with a DC supply with an ESR lower than the LED array and choose a 2V current limiter, or a millivolt current sensor, chopper to regulate the average current with max, efficiency or use a series R that drops < 1 LED diode drop to regulate the array of series and parallel LEDs. I would choose a 19.4V Laptop charger for 6 white LEDs strings and have as many in parallel as you can drive ( 65~150W chargers) chosing the series R to be << 1V drop for each string to be < 0.5W loss)

... or use a standard telephony power supply for 48V for 16 LED strings and choose ESR of LED's to fit desired current and add a low R PTC to regulate it with temp. or use a CC sink or source with 1 less LED if you can afford the loss of efficiency.

ESR of LED's is around 15 Ohms for 5mm @20mA and 1 Ohm for 100mA for power LEDS and @ 100mOhm @ 1Amp.. just for ball-park figures which depends on chip size and OEM supplier.

In CV drive mode ( vs CC) you need to add up ahte Rs or ESR from all sources, LED array, PSU, distribution Wire. For large installations, the wire can be your current regulating feed for parallel operation to prevent thermal runaway coming from a CV source where the LED load drops voltage with rising temp and thus higs current creating a thermal runaway condition which can be eliminated with smaller ESR PTCs eg ( halogen tungsten tube) which will compensate tthe the NTC of the LEDs to achieve a loop NPO curve with less power wasted than CC regulators. Of course SMPS regulators can offer 98% efficiency for 48V strings but required some EMI filtering to drop loop antenna egress.

To the uninitiated, this will sound like nonsense, so ask if you don't understand. I power all my LED high power systems with linear CV compensated parallel lines using inexpensive SMPS chargers. much less than 1$/W