A Very Basic 12 volt Inverter- This circuit will provide a fairly stable "Square Wave" Output Voltage. Frequency of operation is Mainly determined by the 220 uF Feedback Caps. Currently about 60 Hz. Various "off the shelf" transformers can be used. __ Designed by G.L. Chemelec
AC Current Monitor- This circuit uses a small AC current transformer from Magnetek to produce an isolated voltage proportional to the AC current in the primary winding. The transformer contains a single turn primary with a low 0.001-ohm resistance. It can easily handle 30 . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006
AC Power Meter- If you would like to save electric energy, you first of all need to measure the AC current flowing through your appliances. AC line voltage times the measured current value gives the power. Build an AC power meter with a current transformer as shown in the schematic given above. __ Designed by MINOWA, Makoto 7N3WVM
AC to DC (240v to 5v)Power Supply- This is simple way to power some 5v logic from a 240vac source. If a 120vac power adapter is used, the circuit will also work for 120vac power lines . . . Hobby Circuit designed by David Johnson P.E.-February, 2002
AC to DC - Miniature - Power Supply - Electronic systems are getting quite efficient these days. I seldom design a small product that requires more than 100 milliwatts of power. Often, if the product is not going to be powered by batteries, it requires a wall mounted AC to DC power adapter or a small on-board power module. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 15 Jan 2011
AC to DC 18V Power Supply- This is a classic linear power supply which produces a regulated 18v, rated at about 1 amp . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
AC to DC Power Supply requires Low Power- Last month I showed how to use a small common mode choke as a fully isolated transformer and a 130v sidac to generate about 100mw of DC power from the AC line. This second circuit still uses the same inexpensive tiny off-the-shelf 5mH common mode filter coil with a split bobbin as a high frequency transformer but uses two SCRs instead of a sidac to discharge a capacitor . . . Hobby Circuit designed by David Johnson P.E.-November, 2011
AC/DC Bike-Powered Generator System- An exercise bike is fitted with a permanent DC magnet motor, which, charges a 12VDC lead-acid automotive battery. This battery can be used to directly drive DC loads or can be fitted with an AC inverter to drive regular house-hold loads. The system is interfaced through the PC to allow data-logging and monitoring of both instantaneous current, voltage and power along with accumulated power. __ Designed by Greg Miller
AC/DC relay from Charge Coupled MOSFET- This circuit acts as an AC/DC relay with a rating up to 50 volts peak and up to 10 amps of current. The differential oscillator supplies voltage to the gates of the two FETs with good isolation will drawing only 1.5ma of current . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2005
Active Power Zener- Schematic only. __ Designed by Tony van Roon VA3AVR
Adjustable Voltage Regulator- Many amateurs have stopped by their local Radio Shack store and have noticed the famous LM317T adjustable voltage regulator. But, did you know that all voltage regulators are adjustable? Yes, any IC voltage regulator can be adjusted to a higher voltage than its fixed voltage by just adding a couple of resistors __ Designed by Radio Amateur Society of Norwich
Alternative power source for Magellan GPS receivers- This GPS receiver is powered by 2 AA batteries. They are only strong enough for the GPS to stay on for about two hours, and this seems like quite a waste. I would like to be able to use a larger battery, and sometimes even an AC adapter. __ Designed by Ryan Janzen
Amperage Booster for 78xx's- Volt regulators such as the LM708, and LM317 series ( and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be used ( See the project on the 3-part variable power supply) __ Tony van Roon VA3AVR
Amplified Zener - This circuit above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0.7 Volts are dropped across the transistors b-e junction, leaving a higher current 12.3 Volt output supply. This circuit can supply loads of up to 500 mA. This circuit is also known as an amplified zener circuit __ Designed by Mick Devine
An Output Adjustable Flyback Converter- A high voltage step-up DC power supply using adjustable flyback conversion. __ Designed by Andy Collison
AN132 - Fidelity Testing for A to D Converters- Linear Technology AN132 __ Designed by Jim Williams - Oct 1st, 2011
AN17 - Considerations for Successive Approximation A ->D Converters- Linear Technology AN17 __ Designed by Jim Williams - Dec 1st, 1985
AN-60-004 Ultra-Linear 50W Amplifiers 20-512MHz LZY-1- AN-60-004 App Note__ MiniCircuits.com
AN-60-005 Ultra-Linear 32W Amplifiers 500-1000MHz LZY-2- AN-60-005 App Note__ MiniCircuits.com
AN-60-009 High IP3, wide band, balanced linear power Amplifier HELA-10- AN-60-009 Application Note __ MiniCircuits.com
Artificial ground to transform an Unipolar Power Supply into a Bipolar Power Supply- The Approach used here is just an active Voltage Divider. The GND of the Output just has to be centered between the positive and the negative Supply. This can be achieved using a Power OpAmp such as the L149 ( 4A) or the L165 ( 3A) or any equivalent type being available at your local hardware store. The Schematics below shows how to wire __ Designed by Alexander C. Frank, aka Ajarn Changpuak
AT PC Power Supply 1- Schematic only, no text included__
AT PC Power Supply 2- Schematic only, no text included__
AT PC Power Supply 3- Schematic only, no text included__
AT PC Power Supply 4- Schematic only, no text included__
AT PC Power Supply 5- Schematic only, no text included__
Automatic 9-Volt NiCad Battery Charger- BR1 can be a bridge rectifier or four diodes (10A) with a 100 PIV rating. A 10, 000uF/50V electrolytic capacitor completes the filtering of the 28.8V. Yep, C1 is a real clunker. You can use larger if you like, just watch it when you power up. Without a 'power-up' delay circuit of sorts it will probably blow-up the 723 if the capacitor (C1) is too-large. __ Designed by Tony van Roon VA3AVR
Automobile Interior Light Fader- This circuit is similar to the fading eyes circuit above and is used to slowly brighten and fade interior lights of older cars. The circuit is based around the LM324 low power OpAmp which draws around 3mA of current, so it won't bother the battery if left connected for extended periods __ Designed by Bill Bowden
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