• LASER/LED LIGHT OUTPUT INTENSITY METER
  This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure the light power output of infrared and visible LEDs and laser diodes. It can be modified to produce almost any milliwatts to volts scale factor. It can be connected to either a multi-meter or an oscilloscope.

• LIGHT RECEIVER WORKS FROM 1KHz TO OVER 70MHz
  This circuit uses one tiny C-MOS inverter IC to form a modulated light receiver with a very fast response. It is designed around a PIN photo diode that is packaged for use with plastic optical fibers. It can be used as an optical fiber receiver. By using the open end of the optical fiber it can "sniff" out any modulated light signals.

• Low Value Capacitance Meter
  This circuit was originally designed to measure the volume of fluid inside a medical syringe.   As designed, it produces a zero to 5 volt output, corresponding to a capacitance change of about 10 picofarads.  With a digital voltmeter, at its output, it can resolve a capacitance change of 0.002 picofarads or 2 femtofarads.  (added 12/04)

LM2731/LM2733 Evaluation Board:  This evaluation board demonstrates the operation of LM2731/LM2733 and gives information on their usage. The primary difference between the LM2731 and LM2733 is that the LM2731 has a higher current internal switch FET (with lower breakdown voltage), while the LM2733 has a higher voltage FET which handles less current.  (app note added 3/05)

LM2750-5.0 Evaluation Board:  This evaluation board demonstrates the operation of the LM2750-5.0 and gives information on it's usage.  (app note added 3/05)

Load Pulser Tests Supply's Transient Response:  04/11/96 EDN-Design Ideas / (added 3/03)  Modern µPs place severe demands on the transient response of the power source. For example, Intel's P6 specification stipulates an output-current capability of at least 30A/µsec while maintaining output-voltage regulation within specified limits. Building a power supply that meets this requirement....

Load Simulator Maintains Constant Power:  04/11/96 EDN-Design Ideas  / (added 3/03)      

Logic designer and breadboarding system for digital circuits:  (diagram added 05/07)

Logic offers complementary switch Control:  12/06/01 EDN Design Ideas  /  (added 1/05)  The complementary-switch controller in Figure 1 uses a few inverter gates to provide drive signals for the complementary switches. Complementary-switch configurations find widespread use in synchronous-rectification circuits, charge pumps, full-bridge control circuits, and other circuits. The circuit in Figure 1 provides not only a complementary drive signal but also a deadtime delay ... ...

Logic Probe #1:  (electronic schematic / circuit added 4/02)

Logic Probe #2:  with probe (added 5/05)

Logic Probe #3:  with probe, CMOS (added 4/02)

Logic probe that is essential for servicing digital circuits:  (diagram added 05/07)

Logic Probe uses Bicolor LED:  03/13/98 EDN-Design Ideas  / (added 03/03)   

Logic probe with integral pulser function:  (schematic / circuit added 05/07)

Logic Probe with Pulse CMOS:  (schematic added 8/03)

Logic Probe with Pulse:  (electronic schematic / circuit added 4/02)

Logic Probe(3) Audible TTL/CMOS:  (circuit added 9/04)

Logic probe:  (diagram added 05/07)

Logic probe:  (schematic / circuit added 05/07)

Logic pulser with DIP switch for setting output waveform characteristics:  (schematic / circuit added 05/07)

Long-Delay Op Amp Timer:  After some experimentation I ended up with the circuit shown in Fig 2. It comprises a timing capacitor, a FET-input 3140-type IC configured as a voltage follower, and a second IC, a 741, which functions as a voltage comparator and relay driver. (added 03/05)

Loopback Diagnostics using the DP8390/901/902/905:  National Semiconductor Application Note   (app note added 2/06)

LOPIC Logic Probe with Pulser:  (circuit added 9/04)