I'm in need of an amplifier circuit that will amplify a 2.0 VDC. pulse signal to a > 12 VDC pulse signal, so it can be read by an Automation Direct DL06 PLC high speed counter input. I bought some 2n3904 transistors and some 1k, 2k, and 10k resistors hoping I could make them work. It's been a lot of years since I've done anything like this and I need some help designing the circuit. Can anyone help me out? The frequency is going to be around 600 Hz and the input voltage to the high speed counter input needs to be at least 12 VDC.