Electronic Circuits and electronic circuits, electronic schematics plus an extensive resource for hobbyists, inventors and engineers

DiscoverCircuits.com, has 40,000+ electronic circuits, cross-referenced
into 500+ categories.    We have searched the web to help you find quick design ideas.
We make every effort to link to original material posted by the designer. 
Please let us if you would like us to link to or post your design.

HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches

Circuits designed by David Johnson, P.E.
Last Updated on: Monday, July 11, 2016 01:59 PM

Master Category List - Dave's Circuits

Text & Graphics Copyright © David A. Johnson, PE - ALL Rights Reserved.
LINKING to Dave's circuits is permitted but DO NOT COPY to your WEB SITE server!

Receiver Circuits

12v – 24v AC and DC Day/Night Switch  -  The circuit uses a bridge rectifier circuit to convert AC into DC.  A 12v zener diode limits the operating voltage of the circuit to 12v.  A tiny Schmitt trigger inverter and a phototransistor detects the ambient light intensity.  If there is sufficient light, the inverter disables a push-pull oscillator circuit . . . [Hobby Circuit designed by David A. Johnson P.E.,  03/25/12]

 

240VAC to 5VDC 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 . . . [Circuit by David Johnson P.E.,  02/12/02]

 

9v Battery Eliminator  -  If you use 9v battery powered devices for long periods of time, you may get tired of constantly changing batteries. The circuit below can be wired into any 9v battery powered device, drawing power from an external AC to DC power adapter.  I designed the circuit . . . [Circuit by David Johnson P.E.,  12/06/09]

 

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 A. Johnson P.E.,  02/12/02]

 

Battery Eliminator  -  If you use a 1.5v or a 3v battery powered MP3 player for long periods of time, you may get tired of constantly changing batteries. Some older players do not work will NiMH rechargeable batteries so changing out batteries can get expensive.  The circuit be . . . [Circuit by David A. Johnson P.E.,  06/01/05]

 

Circuit Eliminates 9v Battery  -  If you use 9v battery powered devices for long periods of time, you may get tired of constantly changing batteries. The circuit below can be wired into any 9v battery powered device, drawing power from an external AC to DC power adapter.  I designed the c . . . [Hobby Circuit designed by David A. Johnson P.E.,  12/06/09]

 

LM317 adjustable voltage regulator used in Battery Eliminator Circuit  -  If you use a 1.5v or a 3v battery powered MP3 player for long periods of time, you may get tired of constantly changing batteries. Some older players do not work will NiMH rechargeable batteries so changing out batteries can get expensive.  The circuit be . . . [Hobby Circuit designed by David A. Johnson P.E.,  06/01/05]

 

Miniature Pushbutton On/Off Switch  -  In many battery powered devices, you would like to turn the circuit on and off by pressing a small pushbutton switch.  One press turns the device on and second press turns it back off.  The flip/flop circuit below uses a minimum number of parts to perform . . . [Hobby Circuit designed by Dave Johnson P.E.,  10/16/05]

 

Nine-Volt Battery Eliminator  -  If you use 9v battery powered devices for long periods of time, you may get tired of constantly changing batteries. The circuit below can be wired into any 9v battery powered device, drawing power from an external AC to DC power adapter.  I designed the circuit . . . [Circuit by David A. Johnson P.E.,  12/06/09]

 

Touch Switch 240VAC  -  This is another capacitance based touch on/touch off switch, which can control power to a 200 watt 240vac load . . . [Hobby Circuit designed by Dave Johnson P.E.,  02/12/02]

 

Voltage Boost  -  In this design a marginal AC to DC linear power supply provides a voltage boost, so it can maintain regulation at low line voltages.  The added components are wired at the AC input and the + DC output of an existing bridge rectifier circuit. The components act as a full wave “charge pump” which will boost the DC output voltage across the main filter capacitor C3. Without the boost circuit, when the AC line voltage drops to 105vac, the DC output voltage only reaches 11.5 volts, too low for a 12v voltage regulator. . . . [Hobby Circuit designed by Dave Johnson P.E.,  07/18/06]


More  Receiver Circuits
 

Find Dave's Circuits by Category
eMail David A. Johnson, P.E. about these circuits




HOME Schematics Index Hobby Corner Dave's Circuits Electronic Resources Contact Info
Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches


 About Us   |  Advertise on DiscoverCircuits.com   |   Report Broken Links  |    Link to DiscoverCircuits.com  |    Privacy Policy

The circuits on this site are designed by David A Johnson - unless otherwise noted.  David A. Johnson & Associates.  All Rights reserved. 
 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.