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1 Amp Current Injector - When you need to measure resistance down to
a few micro ohms, this circuit works great. It is powered from two "C"
cell batteries and is designed to inject a well regulated one amp of
current into the unknown resistance. By measuring the voltage drop
across the resistor with a digital voltmeter, the resistance value can
be accurately measured. The circuit also is equipped with a low battery
monitor. Published in Popular Electronics, November 1992 ….(designed by
David A. Johnson) |
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AN-D16: LND1 Series: Constant Current Sources And - Supertex
Semiconductors (app note) |
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AN-D18: DN25 Series: Constant Current Sources And - Supertex
Semiconductors (app note) |
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Bipolar current source maintains high output impedance at high
frequencies - 12/05/05 EDN-Design Ideas: Use line-receiver/amp ICs
to build high-frequency constant-current sources.....(design idea) |
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Build a Precise DC Floating Current Source - 08/18/05 EDN-Design
Ideas: Use a general impedance converter and resistors to develop a
specialized current source.....(design idea) |
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Circuit Forms Constant Current SCR - 02/01/01 EDN-Design
Ideas:.....(design idea) |
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Circuit Forms Novel Floating Current Source - 05/01/03 EDN-Design
Ideas: Figure 1 shows a polarization circuit applicable to ISFET
(ion-sensitive field-effect-transistor)sensors. ISFETs are solid-state
chemical sensors that measure the pH value of a solution in biomedical
and environmental applications, for example. The circuit in Figure 1 is
extremely simple; it sets fixed-bias conditions for ISFET sensors (VDS=I0
RX; IDS=I0).....(design idea) |
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Circuit provides constant current for ISFETs/MEMFETs - 10/26/00 EDN-Design
Ideas: ISFETs and MEMFETs (ion-sensitive and membrane FETs) are
solid-state chemical sensors that provide an electrical signal
associated with the change of a....(design idea) |
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Circuit provides constant current load for testing batteries -
02/19/09 EDN-Design Ideas: , A 9V battery provides power for a
constant-current source for testing AA- or AAA-size
batteries.....(design idea) |
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Constant Current Amplifier - (diagram) |
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Constant Current Battery Charger - A simple method of charging a
battery from a higher voltage battery is shown in the circuit below to
the left. Only one resistor is needed to set the desired charging
current and is calculated by dividing the difference in battery voltages
by the charge current. So, for example if 4 high capacity (4000 mA hour)
ni-cads are to be charged at 300 mA from a 12 volt battery, the resistor
need,....(circuit) |
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Constant Current Charger - This simple constant current source uses
an LM317 regulator IC. N.B. The pin-outs of the IC are not a mistake,
the output is taken from the adjustment pin. I found this circuit to
charge all my NiCad batteries, and I use a Kambrook mechanical
light-timer (or equiv.) for 110vac to time the charge.....(John Nooyen's
electronic schematic / circuit) |
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Constant Current Constant Voltage Converter Drives White LEDs
- 09/02/04 EDN-Design Ideas: LEDs usually take their drive from
a constant dc-current source to maintain constant luminescence.
Most dc/dc converters, however, deliver a constant voltage by
comparing a feedback voltage to an internal reference via an
internal error amplifier.....(design idea) |
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DAC & flip flops form constant current source - 04/23/09 EDN-
Design Ideas, Using two flip flops, you can program a
serial-input DAC to produce a constant 4 mA.....(design idea) |
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DN25 Series: Constant Current Sources - Supertex
Semiconductors (app note) |
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High Voltage Linear Regulator & Constant Current - Supertex
Semiconductors (app note) |
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LND1 Series: Constant Current Sources - Supertex
Semiconductors (app note) |
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LT1511 Low Dropout Constant-Current/Constant-Voltage 3a Battery
Charger - DN144 Design Notes (Linear Technology) (app
note) |
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OpAmp can source or sink current - 03/02/06 EDN-Design
Ideas: Bipolar current source beats familiar Howland-current
pump.....(design idea) |
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Shunt Constant Current Source - (electronic circuit) |
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Signal Sources Conditioners & Power Circuitry - AN98 Linear
Technology Eighteen circuits are presented in this compilation.
Signal sources include a voltage controlled current source, an
amplitude/frequency stabilized sine wave oscillator, a
versatile, 0V to 50V wideband level shift and four
sub-nanosecond pulse generators with risetimes as low as 20ps.
Five signal conditioners appear; a unique |
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Simple dual constant current load tests low current power
supplies - 06/21/07 EDN-Design Ideas: You can use a simple
9V-battery-powered constant-current load to test small power
supplies at various loads.....(design idea) |
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Simple Variable Voltage Source - The high current regulator
below uses an additional winding or a separate transformer to
supply power for the LM317 regulator so that the pass
transistors can operate closer to saturation and improve
efficiency. For good efficiency the voltage at the collectors of
the two parallel 2N3055 pass transistors |
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TSM108 Evaluatin Board 12V to 6V DC/DC Converter - The
TSM108 is a step down controller that features constant voltage
and constant current regulation.The Evaluation Board was
designed to allow different converter configurations. Several
options for power semiconductor footprints are available on the
PCB in order to make it adaptable to a wide range of converter
output power. In a first step, ..... (app note) |
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Variable Voltage Source - The high current regulator below
uses an additional winding or a separate transformer to supply
power for the LM317 regulator so that the pass transistors can
operate closer to saturation and improve efficiency. For good
efficiency the voltage at the collectors of the two parallel
2N3055 pass transistors should be close to the output voltage. |
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Zener oscillators - These two circuits are interesting from
an academic point of view. Their practical implementation is
rather critical and it is not easy to get steady operation.
Circuit (a) requires a "cooked" zener: connect it
first to a constant current generator, then increase the
current. |
