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

DiscoverCircuits.com, has 45,000+ 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

Got Designs?
Please eMail
if you want me to link to and/or post your original design Thanks.


Solar Cell Circuits  

Solar Cells:   #'s - E       F - O      P - S       T - Z

Last Updated: January 01, 2018 04:02 AM

Circuits Designed by Dave Johnson, P.E. :

Tiny Solar Panels Using Photodiodes  -  There are times when you would like to harvest just a little bit of energy from the sun.  Unfortunately, there are not many miniature solar panels available.  Most panels are 10 to 50 times larger than needed.   You can make your own and wire in series.  Just as in the larger panels, be sure to insert a small signal diode between the photodiode array and any battery or super capacitor being charged.  The diode will prevent current from leaking back into the array at night. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 20 Nov 2011

Tool Shed LED Light  -  I have a lean-to 8ft by 12ft shed next to my house.  It is full of lawn chemicals and garden supplies.  There were times when I needed to get something from inside the shed during the dead of night.  Early on I had to use a flashlight.  But later, I installed a series of five 12v LED light strips on the ceiling.  Each strip contained 15 3v white LEDs.  The strip had 5 strings of three LEDs, wired in series, with a 150 ohm current limiting resistor. . . . Circuit by David Johnson P.E.-July 14, 2017

Variable Isolated AC Voltage Spans 0VAC to 280Vac -  I designed and built this circuit about 25 years ago.  it came in handy for many projects that were powered from 120 VAC, 240 VAC and 277 VAC.  it provides complete isolation from the power line.  it uses two 1:1 isolation transformers that are wired in parallel. . . Circuit by Dave Johnson P.E.-July, 2000

Water Pump controlled by Solar Power -  A Discover Circuits visitor had a problem.  He needed a simple on/off controller for his solar powered water pump.  His system used two 12v 50 watt solar panels wired in series.  The power from the solar panels drove a submerged water pump.  However, during . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2010

Wireless_Solar_Powered_Sensor   -  A company in sunny Florida needed a DC power supply for a remote sensor. The sensor was connected to a low power microprocessor and a RF transmitter.  When switched on, it quickly transmitted collected data in a short burst.  The transmitter drew a peak current of 1 Amp for about 0.01 seconds from a 3v supply.  The transmitter was turned on only once every 10 seconds . . . Dave Johnson, Lubbock TX-DC Magazine - Issue  5 Jan 2010

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747




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

T3SE -  Charge Rate-Controlled Solar Engine: The all-transistor T3SE works much like a conventional SE: like the Tritium, it fires when the charging current drops below the minimum and after the circuit triggers, positive feedback is used to latch the circuit, resetting at a fixed voltage on the main cap.   __ Designed by Wilf Rigter

Temperature Sensitive Switch For Solar Collector -  This circuit can be used to turn the pump on and off when a solar collector is used to heat a swimming pool, for example.  This way the water in the collector has a chance to warm up significantly before it is pumped to the swimming pool.  A bonus is that the pump doesn’t need__ 

The D1 solar engine -  Nocturnal-Controlled Solar Engine: The D1 solar engine is the original nocturnal solar engine design.  The design is simple, tuneable, but no longer terribly useful (I include it here just for purposes of education and folks' historical interest).   __ Designed by Wilf Rigter

The dual slope-sampling solar engine -  if you had time to experiment with the ALF type SE circuit you may have discovered some of its shortcomings with regard to a Power Smart Head adaptation. The problem is that HCMOS gates are power hungry when used as SE voltage comparators when the analog input voltage is near the CMOS switching threshold. if an HCMOS gate is used without sampling, the chip supply current can be as high as 70mA with the comparator input voltage near the trigger threshold (Vcc / 2). __ Designed by Wilf Rigter

The GBSE (gate boost solar engine) -  The Gate Boost SE uses a 1381, a 2N7000 MOSFET and a 2N3906 with a unique voltage doubler to increase the voltage applied to the gate of the MOSFET.  Normally the 2.6V output of a 1381C is barely able to turn on the 2N7000.  As a result the "on resistance" of the MOSFET is high and much power is wasted.   __ Designed by Wilf Rigter

The MicroPower Solar Engine -  A 'micro power solar engine' has been a goal since my introduction to BEAM Robotics.  I believe that if there wasn't one before, I there is one now.  What i'm presenting to you looks very similar to one of the circuits found in Steven Bolt's web pages.  As you will see, I made only minor changes to that design and not without help.   __ Designed by Ken Huntington

The Miller solar engine -  The Miller solar engine uses a 1381* voltage detector (a.  k.  a.  , a voltage supervisor) IC to drive a voltage-based (type 1) solar engine.  The 1381 is normally used to reset CPUs and Micros when the power supply drops too low for reliable operation.  So 1381s detect and switch when the input voltage crosses the rated upper and lower threshold voltages.  The upper- and lower-switching voltages are slightly overlapped so that the turn-on voltage is a few hundred mV above the turn-off voltage.  This hysteresis keeps input noise (around the switching threshold) from resulting in multiple output cycles as the transition occurs.   __ Contact Eric Seale

The VTSE solar engine -  The VTSE uses the popular 1381 chip and that is its main advantage.  The potentiometer (or two fixed resistors) connects one leg between the output and input of the 1381 and the other leg to the supply voltage.  These resistors acts like a voltage divider when the SE is off and the 1381 output is low.  in that case, the voltage that appears at the 1381 input is determined by the ratio of the pot or the two resistors and is usually set for 2 times rated 1381 voltage.   __ Designed by Wilf Rigter

The Vx2SE solar engine -  The Vx2SE is a simple discrete voltage-doubling SE for driving an LED.  if the load is a red or green LED, J1 is used together with just one red or green LED for threshold detection (no 1381).  For driving a blue LED use two green or red LEDs in series and may require a higher voltage (3V) solar cell.  With 100uf capacitors the flash frequency is 2-3Hz and the R2 and R3 resistors may be omitted.  With very large capacitors (0.01F and up) the frequency is much lower and the resistors can be optimized to stretch the LED "on" time.  The Vx2 solar engines will self trigger but are also sensitive to a drop in light and will trigger from a shadow etc.   __ Designed by Wilf Rigter

Tiny Solar Panels Using Photodiodes  -  There are times when you would like to harvest just a little bit of energy from the sun.  Unfortunately, there are not many miniature solar panels available.  Most panels are 10 to 50 times larger than needed.   You can make your own and wire in series.  Just as in the larger panels, be sure to insert a small signal diode between the photodiode array and any battery or super capacitor being charged.  The diode will prevent current from leaking back into the array at night. . . . Dave Johnson, Lubbock TX-DC Magazine - Issue 20 Nov 2011

Tool Shed LED Light  -  I have a lean-to 8ft by 12ft shed next to my house.  It is full of lawn chemicals and garden supplies.  There were times when I needed to get something from inside the shed during the dead of night.  Early on I had to use a flashlight.  But later, I installed a series of five 12v LED light strips on the ceiling.  Each strip contained 15 3v white LEDs.  The strip had 5 strings of three LEDs, wired in series, with a 150 ohm current limiting resistor. . . . Circuit by David Johnson P.E.-July 14, 2017

Train Detector using Ambient Light & a Photocell -  This photocell is best mounted at tie level between the rails.  The variable resistor adjusts the sensitivity of the circuit.  This circuit can be powered by either 6 or 12 volts - BE SURE to use the proper relay; note that some relays are rated for 5 volts, these should be okay with 6 volts. __ Designed by ML Rollins

Tritium -  Charge Rate-Controlled Solar Engine: The Tritium circuit was the first (to my knowledge) type 3 SE.  As such, it is quite experimental, and should be regarded as a prototype rather than the 'state of the art'!  Nevertheless, it does function reasonably well, and in some circumstances outperforms other solar engines such as the Freds that I have lying around.   __ Designed by Wilf Rigter

Type 1 Solar Engine-voltage controlled trigger -  Voltage controlled trigger - This is by far the predominant form of solar engine, since they are "efficient enough" for most uses, and pretty simple to build.   __ Contact Eric Seale

Type 2-Solar Engine-time controlled trigger -  Time controlled trigger - These aren't terribly efficient, but are handy for 'bots that need activity at specific times.   __ Contact Eric Seale

Type 3-Solar Engine-charge curve differentiated -  Charge curve differentiated (i.  e.  , it triggers when the charge rate of the capacitors slow down) -- These are theoretically the most efficient, though type 3 designs are still in their infancy.   __ Contact Eric Seale

Variable Isolated AC Voltage Spans 0VAC to 280Vac -  I designed and built this circuit about 25 years ago.  it came in handy for many projects that were powered from 120 VAC, 240 VAC and 277 VAC.  it provides complete isolation from the power line.  it uses two 1:1 isolation transformers that are wired in parallel. . . Circuit by Dave Johnson P.E.-July, 2000

Variable Threshold Solar Engine -  The VTSE uses the popular 1381 chip and that is its main advantage.  The potentiometer (or two fixed resistors) connects one leg between the output and input of the 1381 and the other leg to the supply voltage.  These resistors acts like a voltage divider when the SE is off and the 1381 output is low.  in that case, the voltage that appears at the 1381 input is determined by the ratio of the pot or the two resistors and is usually set for 2 times rated 1381 voltage.   __ Designed by Wilf Rigter

Voltage Controlled Solar Engine -  Voltage-Controlled Solar Engine: These designs are based on the Motorola MC34164-* micro power undervoltage sensing IC s.  They're pretty efficient, work at higher voltages than most solar engines, and can provide voltages for other logic circuits (say, a microprocessor).  This page hosts the original Chloroplast by Craig Maynard, as well as some Chloroplast variants by Wilf Rigter.   __ Designed by Craig Maynard

Voltage-doubling Solar Engine -  The Vx2SE is a simple discrete voltage-doubling SE for driving an LED.  if the load is a red or green LED, J1 is used together with just one red or green LED for threshold detection (no 1381).  For driving a blue LED use two green or red LEDs in series and may require a higher voltage (3V) solar cell.  With 100uf capacitors the flash frequency is 2-3Hz and the R2 and R3 resistors may be omitted.  With very large capacitors (0.01F and up) the frequency is much lower and the resistors can be optimized to stretch the LED "on" time.  The Vx2 solar engines will self trigger but are also sensitive to a drop in light and will trigger from a shadow etc.   __ Designed by Wilf Rigter

VTSE: Variable Threshold Solar Engine -  Voltage-Controlled Solar Engine: The "Variable Threshold Solar Engine" is Wilf Rigter's 1381-based design -with a variable "trip" threshold.   __ Designed by Wilf Rigter

Vx2SE solar engine -  The Vx2SE is a simple discrete voltage-doubling SE for driving an LED.  if the load is a red or green LED, J1 is used together with just one red or green LED for threshold detection (no 1381).  For driving a blue LED use two green or red LEDs in series and may require a higher voltage (3V) solar cell.  With 100uf capacitors the flash frequency is 2-3Hz and the R2 and R3 resistors may be omitted.  With very large capacitors (0.01F and up) the frequency is much lower and the resistors can be optimized to stretch the LED "on" time.  The Vx2 solar engines will self trigger but are also sensitive to a drop in light and will trigger from a shadow etc.   __ Designed by Wilf Rigter

Water Pump controlled by Solar Power -  A Discover Circuits visitor had a problem.  He needed a simple on/off controller for his solar powered water pump.  His system used two 12v 50 watt solar panels wired in series.  The power from the solar panels drove a submerged water pump.  However, during . . . Hobby Circuit designed by David A. Johnson P.E.-October, 2010

Wireless_Solar_Powered_Sensor   -  A company in sunny Florida needed a DC power supply for a remote sensor. The sensor was connected to a low power microprocessor and a RF transmitter.  When switched on, it quickly transmitted collected data in a short burst.  The transmitter drew a peak current of 1 Amp for about 0.01 seconds from a 3v supply.  The transmitter was turned on only once every 10 seconds . . . Dave Johnson, Lubbock TX-DC Magazine - Issue  5 Jan 2010

Zener-based solar engine -  Voltage-Controlled Solar Engine:  This design uses a Zener diode to determine the voltage trip level.  Simple variants of this design use LEDs or plain old diodes in series to accomplish the same thing.   __ Designed by Wilf Rigter and Eric Seale

Got Designs?
Please eMail
if you want me to link to and/or post your original design Thanks.


Solar Cells:   #'s - E       F - O      P - S       T - Z


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


Copyright  January, 1998 - January, 2018     David A. Johnson & Associates.  All Rights reserved. 


 Linking is ALLOWED but COPYING any content or graphics to your web site is EXPRESSLY PROHIBITED.