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124 Volt AC Lamp Dimmer Full Wave SCR - (circuit / schematic design added 6/06) |
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125 VAC Lamp Dimmer (full wave SCR) - The full wave phase control circuit below
was found in a RCA power circuits book from 1969. The load is placed in series with
the AC line and the four diodes provide a full wave rectified voltage to the anode of
a SCR. Two small....(electronic schematic added 6/06) |
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Circuit Forms Constant Current SCR - 02/01/01 EDN-Design Ideas:.....(design idea
added 6/06) |
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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. ….(designed by David A. Johnson) |
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Crow Bar #1 - Depending on the setting or R1, when the voltage exceeds a certain
amount, SCR1 triggers, which activates relay RY1 and opens the circuit. S1
resets the SCR by interrupting power to it. This is a simple crow-bar circuit for low
amperage protection, up to 4 amps at 30V max. Adjust the SCR for a model that suits
your needs….(Tony van Roon's electronic schematic / circuit added 08/09) |
Crow Bar #2 - This circuit can be added to any power supply design that does not
have additional circuit protection. When the voltage exceeds either 10V or 30V,
depending on the voltage switch setting via the front panel,
the zener diode ZD1 conducts and fires the gate of the SCR. This provides a
short-circuit over the output voltage and in turn will blow the AC input fuse of the
powersupply you wish to protect.….(Tony van Roon's electronic schematic / circuit
added 08/09) |
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Low Power 12,000 Volt Power Supply - If you need about 12,000 volts DC for an ion
generator this circuit might be the ticket. It draws power from the 120vac power line
but it uses a small 6KV camera flash trigger coil. The output signal is isolated from
the power line. Although the circuit can only deliver about 5uA of current it can
produce dangerous shocks, so be careful. ….(designed by David A. Johnson) |
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Miniature Isolated AC/DC Power Supply - This circuit uses a novel approach to
produce a fully isolated and regulated 5 volts @30ma from the 120vac power line. It
uses two tiny SCRs that alternately discharge two capacitors through a miniature high
frequency transformer. The voltage spikes produced through the transformer are
rectified, filtered and regulated. A very common 8-ohm audio impedance matching
transformer can be used for the transformer. Published in EDN, Feb. 17, 1992
….(designed by David A. Johnson) |
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Nanosecond SCR Switch for Reliable High Current Pulse Generators & Modulators -
MicroNote 601 from Microsem (app note added 6/06) |
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Schmidt trigger - In Dutch. Ik kan me voorstellen dat de lezer zijn
wenkbrauwen fronst, een Schmitt trigger met transistoren? Die maak je toch met een
OpAmp of met daarvoor speciale ontwikkelde IC's. Soms heb je toch het probleem dat je
over een lage voedingsspanning beschikt,...(added 05/08) |
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SCR phase control yields solid state switch - 03/15/01 EDN-Design Ideas: SCRs
(silicon-controlled rectifiers)/ PDF contains multiple circuits scroll to find the one
of interest, or thyristors, have higher current and voltage ratings, lower conduction
losses, and more robustness than triacs. For these reasons, SCRs are better suited to
high-power applications.....(design idea added 6/06) |
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SCR Voltage Regulator - Though not as accurate as a linear or a high-frequency
switching regulator, an SCR voltage regulator wastes little power and creates no RFI.
Designed by Andrew R. Morris (added 09/05) |
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Silicon Controlled Rectifier Model Railroad Throttles & London Model Railroad Group
SCR Throttle - The following is a schematic drawing of a Silicon Controlled
Rectifier type throttle for use on larger scale model railroads. Three versions of
this throttle are shown on this page. They are not sophisticated designs but work well
and are tough and reliable. (added 2/05) |
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Thermostat for 1KW Space Heater SCR controlled - Here is a simple thermostat
circuit that can be used to control a relay and supply power to a small space heater
through the relay contacts. The relay contacts should be rated above the current
requirements for the heater. Temperature changes are detected by a .... (added
6/06) |
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UPGA301A Pulse Circuit Analysis - MicroNote 602 from Microsem (app note
added 08/08/08) |
