Chupacabras‭

I have generated flyback convertor schematic by TI's Webench Power Designer. Parameters: universal AC input (85-265V AC) 5V, 2A output isolated UC3843A controller Basically I understand f...

2 answers  ·  posted 3y ago by Chupacabras‭  ·  last activity 3y ago by a concerned citizen‭

I'm trying to modify a LED torch, and there is a DC-DC booster (1.5 V to 3.3 V) and after that some SOT-23 device which (I assume) keeps constant 90 mA current through LED. I know I could remove th...

2 answers  ·  posted 4y ago by Chupacabras‭  ·  edited 1y ago by Lorenzo Donati‭

When switching a relay there should be a flyback diode. It could be just a diode or diode with resistor in series. I understand there is a difference in the speed of relay switch-off. But what is t...

1 answer  ·  posted 4y ago by Chupacabras‭  ·  last activity 4y ago by Olin Lathrop‭

I read datasheet for PCT2075 temperature sensor and there are some contradicting data about accuracy for me. Page 21: accuracy ±1°C (Tamb = -25°C to +100°C) accuracy ±2°C (Tamb = -55°C to +125°C...

1 answer  ·  posted 4y ago by Chupacabras‭  ·  last activity 4y ago by Olin Lathrop‭

There are circuits that require matched transistors. Whether BJTs or FETs. Like current mirrors, logarithmic amplifiers, etc.. There are some examples: https://www.youtube.com/watch?v=DUlugLSroN8...

1 answer  ·  posted 9mo ago by Chupacabras‭  ·  last activity 9mo ago by Andy aka‭

I have an opto-coupler circuit where is very slow turn off. I can't figure out what is the cause of this problem. It's for UART isolation, with speed 9600 baud. Datasheet: EL357NC Do I have som...

2 answers  ·  posted 1mo ago by Chupacabras‭  ·  last activity 1mo ago by Chupacabras‭

I changed value of resistor R318 from 10 kΩ to 1 kΩ, and that alone significantly improved off-time. From 200 μs to around 25 μs. That is much better. So I looked into datasheet again. I found t...

posted 1mo ago by Chupacabras‭