Bilayer Clamp Amplifier (BC-535)
The BC-535 is the newest version of our popular bilayer clamp amplifier. Warner Instruments is the manufacturer dedicated to supplying an instrument specifically designed for research using planar lipid bilayer technology, and this device forms an integral component of the BLM Workstation.
- Resistive feedback headstage - no reset glitch!
- Reduced noise and wider bandwidth
- Improved stability with gains to 1000 mV/pA
- Digital hold potential
- AutoZero function
- Digital readout of membrane capacitance
- Multi-step 4-pole Bessel filter
- Hold potentials to 1400 mV; currents to 20 nA
Resistive Feedback Headstage
BC-535 has an advanced, dual-resistive feedback headstage which provides high bandwidth and low noise recording. The switchable headstage resistance is automatically selected based on the gain setting. A low current mode provides up to 100 pA of current carrying capability, while the high current mode provides up to 20 nA of current capacity!
The hold control for the BC-535 has been redesigned to function entirely within the digital domain. This unique approach allows the user to make holding potential adjustments in highly reproducible and discrete steps of 1 and 10 mV, up to ±400 mV. Hold potentials up to ±1000 mV or step sizes greater than 10 mV can be applied at the Command Input BNC.s located on the front and rear panels of the instrument.
The large currents flowing through the low resistance aperture prior to membrane formation saturates the amplifier input. Under these conditions, junction potential offsets can be easily nullified by using the AutoZero function. Once armed, the AutoZero cycle measures and compensates for any offset potentials in the conducting pathway. Traditional manual controls remain for making small corrections or for resetting the offset potential without reactivating the AutoZero cycle.
The BC-535 sports a VCO circuit providing auditory feedback during membrane formation. An internal speaker is included and an external speaker output is provided on the instrument rear panel.
This test circuit has been completely redesigned and is used to monitor the formation of the bilayer membrane. A triangle waveform is applied to the command input and the amplitude of the resulting square wave is proportional to the membrane capacitance. When selected, the membrane capacitance is read directly from the meter.
4-Pole Bessel Filter
The filtering capacity if the instrument has been expanded to include a low pass, 4-pole Bessel filter ranging from 0.05 to 20 kHz in 1-2-5 steps. The internal filter can be bypassed for use with external filtering apparatus and allows realization of the instrument.s full 75 kHz bandwidth.
Large capacitance transients are cancelled using both fast (0.-10 ¼s) and slow (0.2 ms) controls. Each control provides separate adjustment of both amplitude and time constant. Maximum capacitance compensation is 500 pF.
Input and output BNC.s have been duplicated or moved to the instrument rear panel except for those requiring user interaction. Front panel BNC.s include Command Input, Vc x 10 and Im Output. Rear panel BNC.s include the headstage connecter, Im Output, Cap Sync, Cap Out, Command In, and Gain and Filter telegraphs. A speaker output is also available on the rear panel.
|Noise||Measured with 8 pole Bessel filter at specified cutoff frequency|
|Frequency Range||Open Input||100 pF at Input|
|DC to 1 kHz||0.060 pA RMS||0.82 pA RMS|
|DC to 100 Hz||0.009 pA RMS||0.28 pA RMS|
|Input Commands||Hold||Digital; 1 or 10 mV steps to ±400 mV maximum|
|Command In||Front and rear external input, 10 V/V (applied voltage is attenuated by 10/100/1000 at the command electrode)|
|Junction Zero||AutoZero or manual adjust. AutoZero lockout feature. Cycle time 1.5 s, correction to ±120 mV|
|Audio||VCO with off switch and volume control, Internal speaker and external speaker output|
|Capacitance Test||Triangle wave applied to command electrode; derived membrane capacitance read from meter up to 1000 pF; calibrated (1 mV/pF) square wave available at Im output; Cap Sync (rear panel) synchronized with input triangle wave|
|Gain||Membrane current gain selectable from 0.5 to 1000 mV/pA in 1-2-5 steps|
|Filter||4-pole Bessel selectable from 0.05 to 20 kHz in 1-2-5 steps, or bypassed for full amplifier bandwidth|
|Capacity Compensation||Fast (0-10 µs) and slow (0-2 ms) with adjustment of amplitude and time constant for each range. Maximum compensation 500 pF|
|Low Current Mode||50 gigohm feedback, 100 pA maximum current|
|High Current Mode||500 megohm feedback, 20 nA maximum current|
|Command Input||BNC input up to 10V. Attenuated by 10, 100 or 1000|
|Im Output||Membrane current scaled by amplifier gain setting|
|Vc x 10 Output||Applied command voltage x10|
|Im Output||Membrane current scaled by amplifier gain setting.|
|Cap Sync||TTL compatible|
|Capacitance output||Reports calculated membrane capacitance scaled to 1 mV/pF|
|Command Input||BNC input up to 10V. Attenuated by 10, 100 or 1000.|
|Gain Telegraph||Stepped DC voltage 0.5 to 5.5 V in 0.5 V steps for gain settings of 0.5 to 1000 mV/pA. Telegraph value of 0 V for bypass mode.|
|Filter Telegraph||Stepped DC voltage 0.5 to 4.5 V in 0.5 V steps for filter settings of 0.05 to 20 kHz. Telegraph value of 5.0 V for full bandwidth (bypass) mode.|
|External speaker||Standard RCA jack|
|Digital Meter||3.5 digit LED||±1999 mV full scale|
|Junction offset||±120 mV full scale|
|Cap Test||0 to 1999 pF|
|Vc||±1999 mV full scale|
|Im||± 1999 pA full scale|
|Warranty||3 years parts and labor|
|Power||100-125 or 220-240 VAC, 50/60 Hz, 20 VA|
H x W x D
|Case||9 x 42 x 25 cm (3.5 x 16.5 x 10 in)|
|Headstage||2.3 x 2.8 x 5.8 cm (0.9 x 1.1 x 2.25 in)
1.8 m connecting cable
|Warner Bilayer Workstation brochure (rev 060601).pdf||Warner Bilayer Workstation Brochure|
|BC-535 prelim (060126)..pdf||BC-535 Manual|
|Connecting the BC-535 to pClamp.pdf||Connecting the BC-535 to pClamp|