Power Control Electronic Circuits


	DiscoverCircuits.com, has 26,000+ electronic circuits or schematics carefully cross-referenced into 500+ categories. As a vital resource for engineers, hobbyists, inventors & consultants, the site's collection of information will help you find quick solutions to electronic design problems.

HOME

Schematics

Discover Forum

Hobby Corner

Dave's Circuits

Electronic Resources

Book Corner

Contact Info

Discover Solar Energy

Imagineering Ezine

Dave Johnson & Associates

Power Control Circuits
Last Updated on: Monday, August 18, 2008 04:17 PM

Circuits Designed by Dave Johnson, P.E. :

CIRCUIT PROTECTS FROM BATTERY POLARITY REVERSAL
This simple circuit can protect a sensitive electronic circuit from an accidental connection of a battery with a reversed polarity. The N-channel FET connects the electronic device to the battery only when the polarity is correct. The circuit shown was designed for a device powered from a single 1.5 volts button cell battery. However, the circuit will operate with higher voltages as well

CHARGE COUPLED BI-DIRECTIONAL POWER MOSFET RELAY
The circuit uses an inexpensive C-MOS inverter package and a few small capacitors to drive two power MOS transistors from a 12v to 15v supply. Since the coupling capacitor values used to drive the FETs are small, the leakage current from the power line into the control circuit is a tiny 4uA. Only about 1.5mA of DC is needed to turn on and off 400 watts of AC or DC power to a load.

SOLID STATE RELAY REQUIRES ONLY 50uA DRIVE CURRENT
This circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays. It is ideal for battery powered systems. Using a combination of a high current triac and a very sensitive low current SCR, the circuit can control about 600 watts of power to load while providing full isolation and transient protection.

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Automatic Control Starts Loads Softly: 10/13/94 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

AutoTransformer Regulator Inverts 12 Volt to Produce 12V: 08/01/97 EDN Design Ideas / (Circuit / schematic design added 6/06) -- Produces Output of200 mA

Automatic Power off Circuit Saves Battery: 12/05/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

Build a UPS for USB devices: 04/11/02 EDN Design Ideas (added 1/05) Portable systems often include circuitry that derives power from an external source, such as USB. When the system disconnects from the USB supply, a battery takes over and supplies current via a dc/dc converter. A diode-OR connection (Figure 1) offers the easiest way to ensure that the supply voltage doesn't sag during this switchover to the battery. ...

Circuit Automates Switch over Between Battery & Source: 12/12/97 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

CMOS Gate implements Reverse Phase Control: 05/21/98 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

Controller Provides Constant Power DC Load: 03/14/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

Isolated Driver Forms Solid State Circuit Breaker: 03/03/98 EDN-Design Ideas / (added 03/03) [file contains multiple circuits - scroll to find this one] -- This circuit allows standard TTL logic levels to safely drive a high-power dc load, circuit provides also overcurrent circuit breaker functionality

Load Switcher Draws only 6 µA: 07/04/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

MicroController Watches, Controls AC Power: 06/22/95 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one] -- circuit allows an isolated microcontroller to both sense and control ac power to an externally plugged-in device

Novel Circuit Controls AC Power: 01/07/99 EDN-Design Ideas / (added 09/05) PDF contains multiple circuits - scroll to find this circuit.

Power source is insensitive to load Changes: 04/04/02 EDN Design Ideas (added 1/05) For the heating and cooling elements common in industrial systems, resistance is not a fixed quantity. These elements include such devices as positive-temperature-coefficient heaters and thermoelectric coolers. Their resistance can change more than 100% during operation, and the result is a change in power dissipation for elements receiving drive from a fixed voltage or current source. ...

Pushbutton Switch Controls Power Supply & µC: 09/25/97 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) [file contains multiple circuits - scroll to find this one]

Short dc Power-line pulses afford remote Control: 10/25/01 EDN Design Ideas (added 1/05) If you face the challenge of adding a second, independently controlled light source to an existing ceiling lamp controlled by a wall switch, you may find that stringing a second power line is impossible. First, you can replace the wall switch by the circuit in Figure 1. Pushing the on switch S1 or S2 for approximately 1 sec inserts the 12V zener diodes D1 or D2 in series with the ... ...

Smart Switch Cuts Transformer turnon Current : 04/23/98 EDN-Design Ideas (added 06/03) [file contains multiple circuits - scroll to find this one]

Soft Start Circuit for Power Amps: (Electronic Schematic / circuit added 4/02)

Soft start Controller is gentle on loads: 11/22/2001 EDN - Design Ideas / (Electronic circuit added 10/03) The control circuit in Figure 1 senses a given load and automatically soft-starts the load by synchronously adjusting the power to that load. You can also manually adjust the power delivered to the load by controling the phase angle of the line voltage across the load. The phase-angle adjustment for every ac half cycle covers 0 to 180 . .