Latest threads in Hobby Electronics Basicsshow only best voted threads
| Subject | Author | Posted | Replies | |
|---|---|---|---|---|
|
|
Extech DMMs -- not a serious tool
Extech DMMs have a "power-saving" feature that powers off the meter after 15 minutes. That's 15 minutes after turning it on, not 15 minutes after last measurement. It beeps a minute before shutting...
7
|
14 years ago
|
7 | |
|
|
general question about pwm and brushless fans
I have a fan I want to use with continuously variable speed. It is a brush less type (specs on this one say 7-12 volts) should work. And it does . . . but won't take PWM directly, it wants to see...
9
|
14 years ago
|
9 | |
|
|
Wire wound Power Resister reactance to AF
I am planing on making a dummy load for an audio amplifier to do some testing and was wondering if this resister would have a significant amount of reactance with frequencies in the range of 20 to...
17
|
14 years ago
|
17 | |
|
|
Question about electrons and voltage
Hi: An electron has charge of 1.602 =D7 10^-19 coulombs. Does this mean that the potential difference -- when comparing the presence to the absence of -- 1 electron would be 1.602 =D7 10^-19 volts?...
7
|
14 years ago
|
7 | |
|
|
Power Factor Optimization
Hello all from a long time lurker! I have been approached by a rep from a small local company trying to sell us a Power Factor Optimizer, claiming 25% to 33% energy savings on our bills (residential...
7
|
14 years ago
|
7 | |
|
|
Replacing Hall Effects Transistor
I just inherited an old MacBook G3 problem with the laptop is that it always thinks that the cover is closed. All of the documentation I have found on the net say that there is a reed switch that...
4
|
14 years ago
|
4 | |
|
|
Circuit to indicate failure of a heating element
I have a water tank with with 2 x 5kW heating elements (on separate supplies). Problem is: one is probably just about enough to supply all the hot water I usually need, so how can I tell when one has...
30
|
14 years ago
|
30 | |
|
|
Building a class A audio amplifier - no audio out
I tried to build this Class A amplifier circuit as a learning experience: with the following modifications: 1. I have no MPSW45, so I built a Darlington out of a 2N2222 and TIP31A. 2. 150k resistors:...
68
|
14 years ago
|
68 | |
|
|
Touching up black anodized alu heat sinks
You're bound to get scratches and scrapes when you buy these in bulk. Even handling/installing them can result in occasional scratches. What are some good marker/paint brands for touching them up? I...
14
|
14 years ago
|
14 | |
|
|
Trickle charging NiCads
I know this is an old topic and I've done a search, but couldn't find a satisfactory answer to the question: What would be a reasonable charging current for a NiCad battery (in terms of its mAh...
28
|
14 years ago
|
28 | |
|
|
Amplitude-to-Frequency and Visa Versa
Hi: Please don=92t get upset at me. I apologize profusely for posting something so similar to yesterday in a different thread. However, you will notice some difference as you read. Does a device that...
1
|
14 years ago
|
1 | |
|
|
Is this device physically-possible?
Hi: Please don=92t get upset at me. I apologize profusely for posting something so similar to yesterday in a different thread. However, you will notice some difference as you read. I was confused when...
9
|
14 years ago
|
9 | |
|
|
Maxim 712 NiMH Charger Cutoff Temperature
I built a NiMH charger based on the Maxim 712 chip some time ago. I didn't implement the temperature cutoff part of the chip's capability, and now would like to do that. Here's the main question: How...
1
|
14 years ago
|
1 | |
|
|
Is this device possible to make?
Hi: Does a device that performs the following conversions and modulations exist? If not, is it possible to construct? Prior to being superimposed on a carrier wave, a modulator signal has its...
14
|
14 years ago
|
14 | |
|
|
Metal sheet with breadboard
Hi All, I've got this breadboard from circuit specialists and when I opened it, I found a sheet of metal inside of exactly the same size as the board. The package doesn't say anything about its...
4
|
14 years ago
|
4 |