With Ohm’s law we calculate the resistance value of the ballast resistor: R = V −V LED1 −V LED2 I = 12−2−4.5 0.03 = 183.3Ω R = V − V L E D 1 − V L E D 2 I = 12 − 2 − 4.5 0.03 = 183.3 Ω. The resistor must have a value of at least 183.3 Ω. Note that the voltage drop across the resistor is 5.5 V. Giving up 0.5 V on either end is a reasonable compromise between reduction of range (20 % total) and demands on the output structure. For example the AD8676 (a precision amplifier with Rail-to-Rail output) can drive 2 kΩ to ground over the entire temperature range with less than 0.25 V drop, and can sink a couple mA with similar drop. Some op Low-Speed Test: 2 9/16-Inch Self-Feed Bit. The last test we ran was with a 2 9/16-inch Switchblade, calling on a much greater level of power from the drill. Here again, the 5.0Ah battery showed its ability to deliver higher power to finish the task, taking 11.26 seconds compared to the 2.0Ah’s 14.60 seconds. Jan 28, 2016 at 1:36 3 Just FYI, the symbol in 19V⎓3.42A (two horizontal lines, top line solid, bottom line broken) is Unicode U+2393 ⎓ "direct current symbol form two". It means 19 volts DC. If the supply was labeled 19V~3.42A that would mean 19Vrms AC instead of 19V DC. – MarkU Even if your LCD is a different type i.e. without the vacant solder pads, you can still convert it to a 3.3V type with the help of the L7660 chip. For this, just build the following circuit on a small veroboard (or a customized pcb), and carefully interface it to your 5V LCD. However, your 5V LCD should be a type with HD44780 (or compatible It is compact, temperature, voltage and current stabilised and give a good reference voltage regardless of input (within limits) provides 1A and is cheap as chips (cheaper in fact). I use the all the time and managed to get 50 (in a tape) for £1.22! They also do different form factors and output voltages (i also use the 5V version). awERp. Also, check that you have the FTDI programmer jumper cap set to 5V. Check the FTDI programmer you are using. One of our readers reported the following: “found out that you can program the board with a USB-to-TTL module model CP2102 and that the CH340 model does NOT work“. This is the FTDI programmer we’re using. Power the ESP32-CAM with 5V Short answer: yes, you can power both with a 12V 4A supply and NO, you can't use 24V 2A supply, it will fry everything most likely. Long answer: If one or both devices is sensitive to noise (eg an audio amplifier), powering two devices from the same supply could create noise that intereferes with normal operation (eg hum in speakers). I would instead find a bulb that works at lower voltage- say 15V or 25 V. Mike W. The headlights in a car have exactly the parameters you desire -- about 50 watts per, and there are two of them, driven in parallel on a 12V car battery. You can easily find 40W halogen bulbs at most hardware stores that run on 12 volts of electricity (AC or DC). to be able to derive V. ΔR. This can introduce additional challenges due to the limitations of standard measurement equipment. For example, a simple 4-digit multimeter used to measure V. OUT. and V. R. could produce rounding errors that affect the calculation of V. ΔR: if the multimeter rounds V. OUT = 3.0015 V up to 3.002 V and V. R = 2.9985 This drops the first LED to 4.3 V, which means a 4.3 V * 0.7 = 3.01 V signal can be used to control it. The logic out of this LED will be at 4.3 V, which is enough to power the rest of the LEDs Whether you mean to use the PNP in common emitter (emitter tied to 5 V) or common collector (collector tied to ground, emitter pulled up to 5 V) configuration, then this circuit will expose the 3.3 V circuit to over-voltage (~4.5 V). At the moment I'm wanting to use the 74hc595. When this is run at 5v it seems to need around 3.7v for an input.

can i use 4.5 v instead of 5v