IMPROVED SCHEMATIC by Bob Beck

The first section (U1B) of the LM358 dual op-amp is a 54 (2 x 27 Volts peak per cycle) volt peak-to-peak square wave oscillator. The second section (U1A) reverses polarity and provides ±27 Volts DC output of low impedance. This delivers a Bi-Phasic, sharp rise-time output of ~4 Hz (not critical) for the biological cotton-covered, stainless-steel (or gold-plated) electrodes saturated with salt water before applying. Sharp rise-time is considered necessary to provide higher odd harmonics to the stimulus, although "rounded" waveforms will feel different.The third section is a current-limited 27 Volts DC output from a separate RCA (or 2.5mm) jack for rapid generation of excellent ionic colloidal silver in water. A three minute cycle in 8 Oz. of room-temperature water makes a ~3-5 PPM concentration.

Op-amp section U1B's 4 Hz oscillator frequency is set by C1 (0.1 uF) and R1 (2.4 meg Ohm). It is configured as a comparator with hysteresis determined by R2 (150 k Ohm). Charging and discharging of C1 is done by the 180º out-of-phase signal through R1. R3 and R4 provide a set-point 1/2 the V+ to the comparator. This insures a 50% duty cycle square wave with an amplitude of slightly less than the ~27 Volt supply.U1A, the second comparator, is used to invert the output of oscillator U1B. A ~54 Volt peak-to-peak signal will be generated between the op-amps due to their outputs being 180º out-of-phase. U1A's current is limited by potentiometer R5 (100 k Ohm) and R7 (820 Ohm) and is set to individual user's comfort.

The power indicator circuit consists of a bicolor (Red-Green) LED (CR1) and the series combination of two 18 Volt Zener diodes, D1 & D2, with power limited by C2 (22 uF, 35 Volt). This section of the device is automatically disabled when the 3.5 mm plug is inserted into its jack. Therefore the LEDs flash only when batteries sum is over ~21 Volts. If LEDs are dim or extinguished, replace with three fresh 9 Volt Alkaline batteries. C2 used as a limiter allows the LED to flicker on at 1/8 second intervals only as the square wave output reverses polarity.Users find this newer design highly satisfactory, trouble free and most efficient.

IMPROVED SCHEMATIC - Parts List
PROPOSED THEORETICAL IN-VIVO BLOOD, HIV, PATHOGEN, PARASITE AND FUNGI NEUTRALIZING DEVICE COMPONENT DESCRIPTIONS AND SOURCESRevision November 24, 1996. Copyright © 1991/1999 Robert C. Beck, D.Sc.

•    LM358 CMOS Operational Amplifier (OP-AMP) chip (generic)       U1
•    2.4 or 2.2 meg ohm ¼ watt 5% resistor                  R1
•    150 k ohm ¼ watt 5% resistor                    R2
•    100 k ohm ¼ watt 5% resistor                    R3, R4
•    100 k ohm linear taper pot, ½ watt Caltronics P-68        R5
•    150 ohm ¼ watt 5% resistor                    R6
•    820 ohm ¼ watt 5% resistor                    R7
•    0.1 uF 50 V or higher ceramic capacitor                C1
•    22 uF 35 V or higher electrolytic capacitor            C2
•    18 Volt Zener diodes (NTE5027A) ½ Watt                D1, D2
•    Bulb: 6-12V @ 55mA or 6.3V @ 0.075 A Type ML612 or 7377        B1
•    Bicolor LED Red/Green RS# 276-012                LED 1
•    3.5mm or 1/8" mono-phone jack                    J1
•    2.5mm or 3/32" mono-phone jack                    J2
•    3 Alkaline 9 V batteries, type 1604 
•    3 x 9 V battery snaps (clip-on connectors) Radio Shack# 270-325 
•    Miscellaneous wire, solder, etc. 
•    Box, if used 
•    Bread-board, if used 
•    8-Pin I.C. Socket, if used 
•    Lead wire with 3.5 mm plug, 6 ft., Mouser or Calrad Electronics 
•    Electrodes, stretch elastic, Velcro, cotton flannel, alligator clips, etc. 

I was able to order everything from eBay with a few modification. ie, TENS pads and wires, reistors with tighter tolerances etc. The entire device can be built-up on a small project board in about 20mins. 

Special Notes

Ensure the IC chip U1 (LM358) is wired correctly. The location of Pin #1 is shown at Left

Source: http://www.sharinghealth.com/bob-beck-build-your-own.html

PS. I've used this unit for sepsis(systematic staph) and a bone infection with very good success. Others have also used it to treat candidas with very good success also. - very positive reports and seems most effective when used in conjunction with colloidal silver.

To add a contribution for the discussion...

A device named spooky2, with a price between 100 and 200 depending on the model, seems to be interesting. It has lots of capabilities for frequencies generation and can be set using a computer with USB connection. It has an acessory that can "listen" the body frequencies in order to identify the frequency of pathogenics to, then, send a "counter frequency" to kill it. The concept seems to be very good, but I do not know about the practical results.

It is able to deliver frequencies up to 20 volts. I placed a question on its forum because Dr. Beck used 27 volts and Sota Silver Pulser uses 31 volts. It is not clear for me if 20 volts is enough to enter deep of if will stay just over the skin:
www spooky2 com/forums/viewtopic.php?f=6&t=944&p=10316&sid=dbf299cb638ff1814781c7c3cb9ce9ea

(Have to subscribe to have access to the forum)