Three inductor-free circuits that allow a white LED or UV LED to be driven from one (1.5 volt) or two flashlight cells (3 volts total) are described. The circuits on this page are: The two cell (3 volt) circuit four transistors. The simple single cell (1.5 volt) circuit requires six transistors, but it isn’t as […]
Single and Two Cell White LED Drivers Without Inductors Read More »
Download FreePC project file, gerber and png copper and silk-screen: 1wattledbuck.zip Introduction I have some 1 watt warm white LEDs left over from a project and the application for them was obvious: A better battery operated lamp for use when the power fails, which it does frequently, especially during the rainy season. And this one should
1 Watt White LED Power Supply Circuit for battery operation Read More »
Overview The circuit shown in Figure 1 is capable of driving an LED array requiring up to several amps with a burst of flashes before coming on until power is removed. It is intended to be used as an auxiliary warning light driver. The initial burst of flashes is meant to enhance visual detection of
Attention-Getting Auxiliary Warning Light Flasher/Driver Read More »
Be Careful About Peak Current A note of caution: These LEDs are comparatively expensive, so I suggest putting a small resistor (1 to 10 Ohms) in series with the cathode of the LED and measuring the peak current as inferred from the IR drop using either a scope or a peak detection probe (as described
White LED Drive Circuit using Tiny microcontroller Read More »
An adapter to allow low capacitance probing of high frequency circuits. Overview My boss, Dave, said “Just hold the probe close to the cathode lead.” Dave had worked at Tektronix for many years, and his ability to make difficult measurements was second only to his abilities to manage a company and design clever circuits. Dave’s
Overview I needed several current probes when designing the deflection circuits and high voltage supply for a computer display monitor, and the lab in which I was consulting only had one current probe, which I shared with the other four engineers on the project. We did not really have a budget for test equipment on
Introduction It has been said that a man with one watch knows what time it is, but a man with two watches is never sure. The same can be said for a person who has more than one voltmeter. In my situation, I have several voltmeters in each of two different locations a third of
A Portable Precision Voltage Reference using microcontroller Read More »
Not too many parts. When a voltmeter is connected across the outside terminals of the output connector, its display reads out in degrees C. I’ve been fascinated by the LM335 for some time -maybe my obsession with stability finally gave way to my fascination with a circuit with intentional thermal drift. I finally bought some
A 128 x 64 graphic LCD is in the clear plastic box at the top. It is connected to the waveform capture and control unit in the green pencil box below the display. Downloads AVR Studio 3.5 ASSEMBLY SOURCE for the waveform capture controller. AVR Studio 3.5 ASSEMBLY SOURCE for the control panel and LED
Minimum Mass Waveform Capture and Display using AT90S2313 microcontroller Read More »
Download auto-zero assembly code This broadband probe has a small antenna (about a 15 cm length of insulated wire). Radio Frequency energy coupled to the antenna is detected and made available to drive millivolt level signals to the input of a DVM (Digital Volt Meter). Its battery powered for convenience with very low current drain
Broadband RF Field Strength Probe using Atmel AT90S1200A AVR controller Read More »
