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Yes the 4017 will work from DC to about 1 MHz. It is a decade counter that may or may not suit your purpose. Here is how to configure it to produce a 10 Hz squarewave having a duty cycle of 40%. Drive the CLK input with a 100 Hz clock. Connect outputs 0, 1, 2, and 3 to a 4 input OR gate or diode OR…

Gunther, the waveforms you have show something a bit different that two phase shifted squarewaves. It appears that you want two squarewaves with some dead time. To generate this type of waveform I have used the 4017 along with diode ORing.

I assume you mean human skin resistance. How you measure this depends on what the measured value will be used for. If used for AC power safety current 50 or 60 Hz is appropriate. I would use a few volts.

The UL leakage current measurement method uses a Low Pass filter to simulate the…

The current source ‘sees’ the 3 nF capacitor in parallel with 50 ohms. Changing the transmission line length should make no difference if the 50 ohm load is ideal. But as you still have some ringing the load isn’t ideal. There is a reflection from the oscilloscope/50 ohm that then travels to the…

Panasonic EEV-FK0J331P
330 uF, 6.3V, 290 m ohm ESR, 300 mA ripple current

Not having specs from you I designed the following circuit that has an exponential current ramp. In simulation:

Tempco = 250 ppm/deg C
Voltage Compliance = 11 volts given a 12 volt power supply
Output Z = 95 k ohms

Nick, I’ll need some specs before designing a soft-start circuit for the LM334.

Specs:

1. Ramp shape, exponential or linear? If exponential how close to 100% current do you need at 5 seconds? I.E. 99%?
2. Maximum fail safe current?
3. Compliance voltage? That is, what is the maximum voltage…

I will assume the switcher is an off-line switcher operating on 240 VAC. The most likely failure is the switching transistor (probably a MOSFET). Using a DMM you can check the MOSFET source-to-drain for a short.

If I understand your circuit correctly the ringing is caused by the reflection at the open end of the cable; the end where the high-Z oscilloscope is connected. Place a 50 ohm shunt at that node it will should stop ringing.

To test an N-channel MOSFET with a DMM and a 9 volt battery:

Tie the MOSFET gate to the source. Set the DMM to “diode” test mode and connect the DMM positive lead to the drain and the negative lead to the source. It should read infinite resistance. Reverse the DMM leads and it should read about…