## Capacitor powered LED flashlight

Long time ago QVC sold a shakeable Flashlight that had no batteries just a shakeable generator and a super capacitor. This flashlight uses a 5vdc 1.5a wall wart to charge the capacitors. To figure out how long it will take to charge the flashlight you use this equation $$T=5R_{currentlimit}C$$ And for total discharge time $$T=5R_{LED}C$$ …

## Yet another TV oscilloscope

In this blog post a crt TV a part and turn it into a oscilloscope. I am going to try to use a TL082 op amp to buffer and amplify the signal. It uses the deflection yoke to draw the picture on the tube. More pictures and videos will be posted here when it is …

## Simplest analog computer

In this post I will show you how to make a analog computer using just resistors, switches and a 100 micro ammeter. Here’s the schematic of it: You can see the idea on how this analog computer works, it uses ohms law to get current from resistors in the circuits. Each current is limited in …

## Solder Iron Foot Switch

This switch is a must for people who solder alot. It prevents the iron from overheating. Its very simple and is very cheap. Some irons like mine can heat back up fast after they have not been cooled down alot. You will need the following parts and tools: 1 foot pedal switch SPST 1 duplex …

## Things you can do with Soundcards

There are a couple things a soundcard could come in handy for electricians. Dual channel oscilloscope and RCL meter/ The first circuit shows you a design for oscilloscope: That circuit gives an impedance <500K on CH1 and CH2. R1 and R2 adjust the voltage range. R3 and R4 is for current limiting resistors for the …