It’s easy to generate DC voltages greater than 12 -13.6 VDC; or if you…
need a regulated -15 VDC, or so for the time base in a spectrum analyzer or sweeper time base. Just ensure you apply correct capacitor and diode polarity. Ply 3 terminal or zener diode regulators as required.
Here’s some circuit examples:
DC-DC converter using a diode “tripler”. I sought 28 VDC to tune some SMT varactors.
Here’s some scope traces (square edges very desirable):
My final version:
I applied some Schottky rectifier diodes in my final version to reduce diode drop losses and allow shunt resistor regulation. With ideal components and no load you should technically get 3 * 12.3v = 36.9 volts. In reality, I got 33.2v because of diode drops, transistor saturation and losses which multiply as the voltage is stepped up. With the shunt 2K7, I measured a low ripple 28 VDC output. I’m happy.
A useful link that shows a bevy of diode doublers/triplers etc.
My Bench Adjustable DC-DC Generator (~24-30 VDC output into a load)
Another way to go — chop an inductor:
Design credit goes to Matjaž, S53MV — permission to use this circuit comes from Andy Barter @ VHF Communications http://www.vhfcomm.co.uk/
My regulated bench supply for applying reverse DC voltage to varactors in circuit under test.
Finally — a cool Bob, K3NHI design using a 600 Ω AF transformer Mouser # 42TM028-RC . Long live the multivibrator!
I used this stage in the USG — Utility Sweep Generator for Bob Kopski’s sweep system. The USG produces an amazingly sharp triangle wave.
Bob’s also clever with generating a little negative DC voltage with a diode. That’s my power meter for use with his sweep system.