Design AM modulator circuit
My (quick and dirty) AM Tx design for a low power personal use requires you know how to generate the input frequency amplitude exactly or at least close enough for personal use.  Using the low end of the AM makes it easier to listen to and use a 1m wire as a loop antenna in series with the 10K resistor to limit power to 1mW with a 9V battery and a low ESR e-cap across the battery with short leads to everything.
Stray capacitance to ground will lower the tuning frequency significantly ( not intended to be a great design resulting in a change in amplitude and bandwidth of the audio.
You can use a XTal or PLL or even a Relaxation Oscillator if stable enough then an R divider to get the correct level.
RF input 1Vpp  in the Lowest AM range. ( ~&gt; 520kHz or between channels)
Audio input @Vpp max
9V battery current  250uA idle and 500uA with full modulation.

Every part serves a purpose.  The main part for the LC on the collector is to always have Vce avg= Vbat and act as a BPF to input RF or a crude channel filter for harmonics.
The resistors are selected to yield 1mW of RF out with minimal current from a 9V battery and almost 100% AM with 2Vpp audio input such as from a smart phone.
No that with no audio input the RF output goes to 1Vpp steady carrier in this design and thus full modulation goes from0 to 2Vpp.  Real AM broadcast Txers are much more complicated with audio compression and a lot more.
For fun, change the antenna wire length or put in series with the inductor instead and keep away from metallic or your body to avoid detuning it a bit.  It's very low power and safe.
When in doubt measure your DC voltages everywhere then Vac.  Have fun.